Changing bus name not properly handled in arcs

[m-bossart]

When changing a bus name, something is corrupted in the system references making it not possible to remove an arc that was attached to the same bus.

To reproduce:

using PowerSystems 
using PowerSystemCaseBuilder

# Works as expected: 
sys = build_system(PSITestSystems, "c_sys5")
br = get_component(Line, sys, "1")
arc = get_arc(br)
remove_component!(sys, br)
remove_component!(sys, arc)

# Changing the name of the bus causes an error when trying to remove the attached arc: 
sys = build_system(PSITestSystems, "c_sys5")
b = get_component(ACBus, sys, "nodeA")
set_name!(sys, b, "nodeA_newname")
br = get_component(Line, sys, "1")
arc = get_arc(br)
remove_component!(sys, br)
remove_component!(sys, arc)

Stacktrace:

ERROR: ArgumentError: component Arc name=nodeA_newname -> nodeB is not stored
Stacktrace:
 [1] _remove_component!(::Type{…}, components::InfrastructureSystems.Components, name::String; remove_time_series::Bool, remove_supplemental_attributes::Bool)
   @ InfrastructureSystems ~/.julia/packages/InfrastructureSystems/yetBs/src/components.jl:187
 [2] 
   @ InfrastructureSystems ~/.julia/packages/InfrastructureSystems/yetBs/src/components.jl:145
 [3] remove_component!
   @ ~/.julia/packages/InfrastructureSystems/yetBs/src/components.jl:139 [inlined]
 [4] remove_component!(data::InfrastructureSystems.SystemData, component::Arc)
   @ InfrastructureSystems ~/.julia/packages/InfrastructureSystems/yetBs/src/system_data.jl:404
 [5] remove_component!(sys::System, component::Arc)
   @ PowerSystems ~/Documents/PowerSystems.jl/src/base.jl:1282
 [6] top-level scope
   @ ~/Documents/PowerSystems.jl/_test_dev_remove_arcs_bug.jl:18
Some type information was truncated. Use `show(err)` to see complete types.

[daniel-thom]

In PowerSystems.jl the Arc name is derived from the bus names. We need to implement a custom set_name!(::System, ::Bus, ::String) method in PSY that re-keys affected arcs in the IS component dict.

Or change how we name arcs. That might be better.

Recommendation: create a new UUID and convert it to string as the arc name. This is in contrast with using the existing UUID because that can also be changed. The downside is that the name is not human readable. We could make a special method for that.

Is a human readable Arc name important @jd-lara ?