Prepare Bazel for Pigweed

[michael-christen]

###Large Changes

• hermetic C++ compilation with clang toolchain
  • had to remove a few gcc specific copts
• commented out rust targets see rust_* is broken: Pigweed's Usage of Clang Breaks rust_library usage #90
• Updates bazel from 7.2.1 to a specific commit of 8.0.0-pre

Miscellaneous Changes

• Updated .bazelignore to ignore bazel-bin, bazel-out, bazel-testlogs
• add -diff to .gitattributes for our big lock files so when diffing we
  just see it as a "binary" and don't make git diff unintelligible
• Fixed location of try-import in .bazelrc (should always be last)

NOTE: You can add per_file_copts with --per_file_copt, for example to
ignore warnings in third_party code

Followup

• add support for stm32 and rp platforms

Related Issues:

• rust_* is broken: Pigweed's Usage of Clang Breaks rust_library usage #90
• protobuf bazel module stuck at 24.4, 26.0 causes segfault when constructing descriptor_pb2.py #91

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (8bac5f9) to head (e21eaf6).

Additional details and impacted files

@@            Coverage Diff            @@
##            master       #88   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            8         5    -3     
  Lines           82        54   -28     
=========================================
- Hits            82        54   -28     

see 7 files with indirect coverage changes