Azure Service Bus client library samples for JavaScript

[service-bus] Samples overhaul (#6997)

* [service-bus] samples: flattened folder hierarchy

* [service-bus] samples: use shared prep-samples

* [service-bus] ts-samples: updated

* [service-bus] ts-samples: changes to align with other packages

* Fixed proxy sample

* Added typescript README and package.json

* Fixed some env var references

* remove extraneous import

* Generate javascript files from TS source

* Fixed URL paths in TypeScript samples

* sample.env and README for js samples

* tsconfig for package-level builds

* Added execute scripts for samples.

* Fixed reference to sample name in typescript readme

* export main in typescript atomManagementApi sample

* removed extraneous returns; fixed r

* Expanded alternative string literals to env vars

* regenerated js samples

* ran prettier on ts samples

* Updated serbvice-bus/samples/README.md

* Removed lib entry from tsconfig

* README fixup