An ill-fated experiment with using a format that was closer to
Bazel left Blueprint preferring the original style, but documenting
and using the new style. Update the documentation and run bpfmt -w.
Test: builds
Change-Id: I3fb70c8fa50c332da01cf5912b179c60d1638814
Forcing module names to be valid ninja names is an unnecessary
restraint on the project build logic. Allow any string as a
module name, and sanitize and uniquify the module name for use
in module-scoped variables.
Also move the module scope to be per-module instead of per-group
so that modules can use the same local variable name for each variant.
Change-Id: If44cca20712305e2c0b6d6b39daa5eace335c148
