Doc generation improvements with UniFFI library mode

[bendk]

Added a tool to run uniffi-bindgen in library mode. One nice thing about this is that it's much easier to figure out the library path in Rust than a shell script.

Use that script to simplify the generate docs scripts.

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  • This PR follows the breaking change policy:
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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 22.00%. Comparing base (7625a2c) to head (e4bd0c4).

❗ There is a different number of reports uploaded between BASE (7625a2c) and HEAD (e4bd0c4). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (7625a2c)	HEAD (e4bd0c4)
	2	1

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #6383       +/-   ##
===========================================
- Coverage   52.72%   22.00%   -30.73%     
===========================================
  Files         125      342      +217     
  Lines       12820    30721    +17901     
===========================================
  Hits         6759     6759               
- Misses       6061    23962    +17901     

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[bendk]

Closing this so that I can rebase it on top of Bastian's PR and also because it's going to need mozilla/uniffi-rs#2240 since we're upgrading to UniFFI 0.28.1.