[Microsoft Generator CSharp] Migrate Writers: Writer Helpers

[jorgerangel-msft]

The writer helper classes should be migrated and stripped of any branding.

Classes to migrate:

• FormattableStringHelpers
• RequestWriterHelpers
• ResponseWriterHelpers

Tasks

Beta Give feedback

1. Migrate Writer Helpers: FormattableStringHelpers #4560
   MGC +1
2. Add RestClient CreateRequest methods to RestClient class #4561
   3 of 3
   Epic MGC +2
   
3. Add protocol send method to Client class #4562
   MGC +1

[m-nash]

@AlexanderSher can you update with which of these will exist.

[m-nash]

@jorgerangel-msft can we split this up to 1 issue per class and put them in mid may iterations

[ArcturusZhang]

@AlexanderSher @m-nash I hope there could be a refactor around these types such as Alexander has done in his consolidation PR before we "migrate" them there because these "writer" helpers are really messy and not following the principal we would like to establish that the writers should just know nothing about what it is writing and everything should be prepared and built in the type provider (including models and clients).
I feel quite a lot pain while making the changes to update SCM around them.