[media] move GainControl to fuchsia.media.audio (reland)

This is a reland of 5496ab442b84258da77d8f1bfeabd690acec029b

Original change's description:
> [media] move GainControl to fuchsia.media.audio
>
> This CL moves the FIDL definition for GainControl from fuchsia.media
> to fuchsia.media.audio. Other audio-related definitions from
> fuchsia.media will be moved later. This is happening now, because
> there are no out-of-repo references to GainControl at the moment.
>
> TEST: no behavior change
> Change-Id: Ia735f6fb2336fbc0ad94933f4b90f8879079804c

Exempt-From-Owner-Approval: previously approved by kulakowsi@

Change-Id: Iadeb46b51969282bec37bc579525af985896d953
43 files changed
tree: c6b1ff29c2e76b86a4be3ee9a7c309a58c70df9f
  1. boards/
  2. build/
  3. buildtools/
  4. bundles/
  5. docs/
  6. examples/
  7. garnet/
  8. peridot/
  9. products/
  10. scripts/
  11. sdk/
  12. src/
  13. third_party/
  14. tools/
  15. zircon/
  16. .clang-format
  17. .dir-locals.el
  18. .gitattributes
  19. .gitignore
  20. .gn
  21. AUTHORS
  22. BUILD.gn
  23. CODE_OF_CONDUCT.md
  24. CONTRIBUTING.md
  25. LICENSE
  26. OWNERS
  27. PATENTS
  28. README.md
  29. rustfmt.toml
README.md

Fuchsia

Pink + Purple == Fuchsia (a new operating system)

What is Fuchsia?

Fuchsia is a modular, capability-based operating system. Fuchsia runs on modern 64-bit Intel and ARM processors.

Fuchsia is an open source project with a code of conduct that we expect everyone who interacts with the project to respect.

How can I build and run Fuchsia?

See Getting Started.

Where can I learn more about Fuchsia?

See the documentation.