[SwiftSyntaxCodeActions] Move SwiftRefactor code actions in from swift-syntax

[25harsh]

Moved SyntaxRefactoringProvider types mentioned in #2639 out of swift-syntax and intoSources/SwiftSyntaxCodeActions/.
Made access specifier changes and dependency changes.

Companion PR #3345

Notes:

1. Removed compiler(>=6) checks

2. Ported helpers from Sources/SwiftRefactor/SyntaxUtils.swift to Sources/SwiftSyntaxCodeActions/SyntaxRefactoringCodeActionProvider.swift

3. Test cases are yet to be moved.
   RemoveSeparatorsFromIntegerLiteral, RemoveRedundantParentheses andConvertStoredPropertyToComputed need coverage. (follow-on PRs)

4. Helpers moved DeclModifierRemover & IntegerLiteralUtilities

[ahoppen]

Thanks for the PR, @25harsh. I have two requests:

• Could you ensure that each file has a trailing newline and that they pass the swift-format check as described in CONTRIBUTING.md?
• Could you also migrate the tests to SourceKit-LSP. If they need some adjustment, that’s fine. I just don’t want to add the refactoring actions here without test coverage.

[25harsh]

@ahoppen all changes are done, overloaded assertRefactor for SyntaxRefactoringProvider that accepts some SyntaxProtocol for input and expected to avoid ambiguity