Extract manifest target metadata

This parses target metadata from manifest files into an in-memory
representation, verifying its validity in the process.

Change-Id: I71a060126f92d20e641f7800c76da8361ad0b847
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/qg/+/125130
Reviewed-by: Erik Gilling <konkers@google.com>
Commit-Queue: Alexei Frolov <frolv@google.com>
8 files changed
tree: 625e1b71bac009e402cc6f36fbef4226c2cc09c0
  1. examples/
  2. qg/
  3. qg-cli/
  4. tools/
  5. .gitignore
  6. Cargo.toml
  7. rustfmt.toml