Break targets that define srcs as glob or filegroup into single-file targets

[angeloprobst]

There are some cases like this:

filegroup(
    name = "py_files",
    srcs = glob(["*.py"]),
)

py_library(
    name = "hyperon_das",
    srcs = [":py_files"],
    deps = [...]
)

Where a single target globs all source files.

This does not help bazel to make the best decision about doing or not a re-build or a re-test of cached targets. Usually, this leads bazel to do more re-builds and re-tests than necessary.

Ideally, each source code file should have its own target and be listed in the deps parameter of who depends on it.

NOTE: same can be found in the CPP code, not only in Python targets.