Upstream the Prism RBS rewriter changes

[KaanOzkan]

It's a large branch so we should try to extract PRs out of it as often as possible. Code will not be triggered.

We should first open the extracted PR against Shopify/sorbet and get team feedback. Some of these files are still going through changes, we should prioritize the ones with less volatility.

Ensure that each file goes through a cleanup before opening a PR: #764

• Parser API changes & triggers in pipeline.cc
  • Add RBS Prism Infrastructure Stubs and Parser API Improvements sorbet/sorbet#9587
• PMK Helpers (parser/prism/Helpers.cc/.h)
  • Add Prism AST node factory sorbet/sorbet#9667
• MethodTypeToParserNodePrism
• TypeToParserNodePrism
• RBSMethodCommon
• CommentsAssociatorPrism
• SigsRewriterPrism
• AssertionsRewriterPrism
• TypeParamsToParserNodesPrism
• SignatureTranslatorPrism
• pipeline_test_runner.cc