First pass at Bazel for iOS developers and outline

[jerrymarino]

This document is an introduction to Bazel for iOS developers.

Putting this up in the current state to get feedback and suggestions
from the community

[rahul-malik]

This is a pretty helpful guide, I would get a handful of product engineers less familiar with Bazel to read through and see if it makes sense or if clarifications are needed.

It could be cool at the end to demonstrate how to use things like bazel query or writing a simple custom rule to show off the advantages

[jszumski]

I suggested some grammar and typo fixes, but overall this is fantastic! I think there's an opportunity to beef up the "Fixing common Bazel errors" section with a few more examples.

[BalestraPatrick]

Suggested change

	In an Xcode world, folks checked in a project which contains an listing of
	In an Xcode world, folks checked in a project which contains a listing of

[BalestraPatrick]

Does Xcode pick it up directly from derived data path? I guess it's worth mentioning that Tulsi manages that at least, otherwise one may think that it works out of the box with just a run script phase that builds the app.

[jerrymarino]

@BalestraPatrick This is a really good point, simply put, yes we currently rsync artifacts into the built products in derived data for xcode to pick it up.

For our internal simulator dev builds, there's a much more performant code path than what Xcode can do. We have a dynamic library architecture and integration where dyld3 loads dylibs residing in bazel-out via an rpath written into the binary. This is probably too in-depth and should be in a performance optimization segment along with the rules that allow this.

[jerrymarino]

Thank you all kindly for your contributions and edits to this document. So many thanks to @rahul-malik and @garrettmoon and @jszumski @BalestraPatrick for all the edits!