Add ts-protoc-gen-library rule to generate protos using Bazel

[easyCZ]

In order to improve support for Bazel, we should introduce a rule to allow generation of TS protos idiomatically with Bazel.

The benefits

1. Ability to synchronise generated code for multiple targets
2. Native experience for Bazel users
3. Contribution to the ecosystem of Bazel

How

A ts_proto_library already exists (docs) leverages Protobuf.JS. We can utilize the learnings from there to add a similar rule.
The code should be contributed to rules_typescript for uniformity but we should test against the rule ourselves on our CI.

Notes

Initial research of this shows this should be very doable and can provide better integration with Bazel than Protobuf.JS as we can choose to compile individual protos based on the dependency analysis from Bazel.

If you have a use case for ts-protoc-gen and Bazel, please let us know so we can better cater for it.

[easyCZ]

Current progress is on https://github.com/easyCZ/rules_typescript/tree/feature/ts-protoc-gen

[coltonmorris]

I've opened a pull request in this repo with the rule here.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.