Migrate to fetch and tsup

[itssimon]

• Simplify build process for both CommonJS and ESM with tsup, replacing Babel
• Fix type resolution for NestJS apps that use --moduleResolution=node
• Use Are the Types Wrong (attw) to check that subpath modules and types resolve correctly
• Remove dependency on axios and use fetch with fetch-retry instead

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 81.63265% with 9 lines in your changes missing coverage. Please review.

Project coverage is 90.02%. Comparing base (e6688af) to head (fe0079d).

Files	Patch %	Lines
src/common/client.ts	81.63%	9 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #20 +/- ## ========================================== - Coverage 90.38% 90.02% -0.37% ========================================== Files 15 15 Lines 1290 1303 +13 Branches 117 122 +5 ========================================== + Hits 1166 1173 +7 - Misses 122 128 +6 Partials 2 2 ```

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