Add additional argument to write_source_file macro: out_file_is_select = False, that enables support for defining select dictionary as out_file.

[geonik-code]

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NOTE: This change is not tested in all cases. It serves as sample implementation for:
FR: write_source_files and write_source_file shall support select() #781

Type of change

• New feature or functionality (change which adds functionality)

• Relevant documentation has been updated

• Suggested release notes are provided below:

Test plan

• Manual testing; please provide instructions so we can reproduce:

write_source_file(
    name = "write_foo_c",
    in_file = ":foo.c",
    out_file = {
        "//conditions:default": "//workspace/subdir:foo.c",
    },
    executable = False,
    additional_update_targets = [],
    suggested_update_target = ":write_foo_h",
    diff_test = True,
    check_that_out_file_exists = False,
    out_file_is_select = True,
)

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