bazel-zig-cc v1.0.0-rc1

Changelog since v0.9.2:
- [Motiejus Jakštys] rename absolute_path to zig_path
- [Motiejus Jakštys] defs: fix import paths
- [Ken Micklas] WIP: use relative paths for tools
- [Motiejus Jakštys] upgrade to zig 0.10.0-dev.4166+cae76d829
- [Motiejus Jakštys] partially revert c023c217a52fb2a2a863c741743fbc1a9c2393e3
- [Motiejus Jakštys] Revert "bump to zig 0.10.0-dev.3999+fda6d4477"
- [Motiejus Jakštys] update README
- [Motiejus Jakštys] contrib/own_zig.md: clarify zig-bootstrap instructions
- [Ken Micklas] Fix include root path for macos-aarch64
- [Ken Micklas] Move Label dependencies above archive fetching to reduce restarts
- [Motiejus Jakštys] bump to zig 0.10.0-dev.3999+fda6d4477