Build: bundle / concat entry points (#161161)

* perf - concatenate windows main files

* Revert "Revert "Use `esbuild` to bundle some CommonJS main files (#160957)" (#161118)"

This reverts commit 84c46b71a5d292a0a9c6cae60e850088270db37d.

* build - exclude server main files

* build - make concat a task that runs like the others

* some renames

* Avoid overwriting the nodejs closure require

* Revert "build - exclude server main files"

This reverts commit 736516624ea73fd13a4e2ac5359e5b54ec851553.

Co-authored-by: Alex Dima <alexdima@microsoft.com>