[Epic] Adopt all changes in dev-tool admin migrate-package and migrate to esm/vitest

[MaryGao]

In this epic we want to adopt our recent changes of migrating all projects to esm/vitest(see issue) into code generator so that we don't require an additional command or other manual effort during release.

The changes happen in existing HLC and RLC but also in our new Modular and RLC with generating from typespec. As a reference here are 4 example' prs for this effort:

• Modular migration pr
• RLC from typespec migration pr
• RLC from swagger migration pr
• HLC migration pr

Tasks

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1. [Modular] Ensure the metadata is the latest and update tsconfig.json #3019
   HRLC p0 +2
2. [Modular] Update codes in README as code snippets way #3024
   HRLC p0 +2
   
3. [RLC from typespec] Ensure the metadata is the latest and update tsconfig.json #3020
   RLC p0 +2
4. [RLC from typespec] Update codes in README as code snippets way #3025
   RLC p0 +2
   
5. [RLC from swagger] Update source files with js suffix in imports #3021
   P1 RLC +2
6. [RLC from swagger] Update metadata files including package.json, tsconfig.json and api-extractor.json #3026
   P1 RLC +2
7. [RLC from swagger] Update test framework to vitest including configurations and import in test files #3027
   P1 RLC +2
8. [RLC from swagger] Update the default moduleKind setting to esm #3028
   P1 RLC +2
9. [HLC] Update source files with js suffix in imports #2987
   +0
10. [HLC & Modular] Update samples with dotenv changes #2988
    CodeGen P1 +2
    
11. [HLC] Update metadata files including package.json, tsconfig.json and api-extractor.json #3029
    CodeGen P1 +2
12. [HLC] Update test framework to vitest including configurations and import in test files #3030
    CodeGen P1 +2
13. [HLC] Update the default moduleKind setting to esm #3031
    CodeGen P1 +2
14. Remove all cjs configs and logic including HLC, RLC and Modular #3032
    P2 +1
15. [HLC] Update codes in README as code snippets way #3051
    HRLC +1
    
16. Update the getStarted doc to include the migration step #3072
    +0
17. [HLC] update the metadata for api-extractor.json #3073
    HRLC +1
18. [Modular] update the metadata for api-extractor.json #3074
    HRLC +1
19. [HLC] Remove Impressions in readme.md #3075
    HRLC +1
20. Generate correct readme, sample.test, snippets.ts files for multi-client in modular #3048
    HRLC P2 RLC +3