Add support for space separator when auditing CLI options

[matlaj]

Ref issue: #2095

This change adds support for auditing --flag value and flag value style command line options.

Previously, CLI options with a space as separator fell through to the bool-flag branch, detecting "true" instead of the actual value.

The key fix is to the separator capture group: = and : are now optional.

To improve readability, capture groups in pttn are now defined separately and later concatenated, with comments providing explanations for their purpose.

Additionally:

• The separator match is not a capture group anymore: its result was unused
• Replaced ^\s with the equivalent \S
• Removed unnecessary trailing *

New test cases verify the change.

[CLAassistant]

All committers have signed the CLA.

[matlaj]

Results without and with this PR, using the toy scenario described in the linked GH issue:

Without

$ ./kube-bench run --benchmark=cis-1.12 --group=4.1 --config-dir=./cfg/ -v=3
(...)
I0508 00:30:24.788585   68409 check.go:110] -----   Running check 4.1.1   -----
I0508 00:30:24.798892   68409 check.go:309] Command: "/bin/ps -fC tail"
I0508 00:30:24.798937   68409 check.go:310] Output:
 "UID          PID    PPID  C STIME TTY          TIME CMD\nmate       35411   24916  0 May07 pts/12   00:00:00 tail -f --lines 5 --sleep-interval=4 /dev/null\n"
I0508 00:30:24.799012   68409 check.go:231] Running 1 test_items
I0508 00:30:24.799103   68409 test.go:153] In flagTestItem.findValue true
I0508 00:30:24.799139   68409 test.go:247] Flag '--lines' exists
I0508 00:30:24.799173   68409 check.go:255] Used auditCommand
I0508 00:30:24.799256   68409 check.go:287] Returning from execute on tests: finalOutput &check.testOutput{testResult:false, flagFound:false, actualResult:"UID          PID    PPID  C STIME TTY          TIME CMD\nmate       35411   24916  0 May07 pts/12   00:00:00 tail -f --lines 5 --sleep-interval=4 /dev/null", ExpectedResult:"'--lines' is equal to '5'"}
I0508 00:30:24.799298   68409 check.go:184] Command: "" TestResult: false State: "FAIL" 
I0508 00:30:24.799336   68409 check.go:110] -----   Running check 4.1.2   -----
I0508 00:30:24.809876   68409 check.go:309] Command: "/bin/ps -fC tail"
I0508 00:30:24.809913   68409 check.go:310] Output:
 "UID          PID    PPID  C STIME TTY          TIME CMD\nmate       35411   24916  0 May07 pts/12   00:00:00 tail -f --lines 5 --sleep-interval=4 /dev/null\n"
I0508 00:30:24.809924   68409 check.go:231] Running 1 test_items
I0508 00:30:24.809969   68409 test.go:153] In flagTestItem.findValue 4
I0508 00:30:24.809997   68409 test.go:247] Flag '--sleep-interval' exists
I0508 00:30:24.810007   68409 check.go:255] Used auditCommand
I0508 00:30:24.810039   68409 check.go:287] Returning from execute on tests: finalOutput &check.testOutput{testResult:true, flagFound:false, actualResult:"UID          PID    PPID  C STIME TTY          TIME CMD\nmate       35411   24916  0 May07 pts/12   00:00:00 tail -f --lines 5 --sleep-interval=4 /dev/null", ExpectedResult:"'--sleep-interval' is equal to '4'"}
I0508 00:30:24.810084   68409 check.go:184] Command: "" TestResult: true State: "PASS" 

With

$ ./kube-bench-fix run --benchmark=cis-1.12 --group=4.1 --config-dir=./cfg/ -v=3
(...)
I0508 00:29:13.648643   68039 check.go:110] -----   Running check 4.1.1   -----
I0508 00:29:13.659218   68039 check.go:309] Command: "/bin/ps -fC tail"
I0508 00:29:13.659262   68039 check.go:310] Output:
 "UID          PID    PPID  C STIME TTY          TIME CMD\nmate       35411   24916  0 May07 pts/12   00:00:00 tail -f --lines 5 --sleep-interval=4 /dev/null\n"
I0508 00:29:13.659297   68039 check.go:231] Running 1 test_items
I0508 00:29:13.659364   68039 test.go:168] In flagTestItem.findValue 5
I0508 00:29:13.659400   68039 test.go:262] Flag '--lines' exists
I0508 00:29:13.659434   68039 check.go:255] Used auditCommand
I0508 00:29:13.659482   68039 check.go:287] Returning from execute on tests: finalOutput &check.testOutput{testResult:true, flagFound:false, actualResult:"UID          PID    PPID  C STIME TTY          TIME CMD\nmate       35411   24916  0 May07 pts/12   00:00:00 tail -f --lines 5 --sleep-interval=4 /dev/null", ExpectedResult:"'--lines' is equal to '5'"}
I0508 00:29:13.659527   68039 check.go:184] Command: "" TestResult: true State: "PASS" 
I0508 00:29:13.659544   68039 check.go:110] -----   Running check 4.1.2   -----
I0508 00:29:13.669357   68039 check.go:309] Command: "/bin/ps -fC tail"
I0508 00:29:13.669399   68039 check.go:310] Output:
 "UID          PID    PPID  C STIME TTY          TIME CMD\nmate       35411   24916  0 May07 pts/12   00:00:00 tail -f --lines 5 --sleep-interval=4 /dev/null\n"
I0508 00:29:13.669440   68039 check.go:231] Running 1 test_items
I0508 00:29:13.669494   68039 test.go:168] In flagTestItem.findValue 4
I0508 00:29:13.669528   68039 test.go:262] Flag '--sleep-interval' exists
I0508 00:29:13.669581   68039 check.go:255] Used auditCommand
I0508 00:29:13.669616   68039 check.go:287] Returning from execute on tests: finalOutput &check.testOutput{testResult:true, flagFound:false, actualResult:"UID          PID    PPID  C STIME TTY          TIME CMD\nmate       35411   24916  0 May07 pts/12   00:00:00 tail -f --lines 5 --sleep-interval=4 /dev/null", ExpectedResult:"'--sleep-interval' is equal to '4'"}
I0508 00:29:13.669658   68039 check.go:184] Command: "" TestResult: true State: "PASS"