##### SUMMARY
If you have executable files in your source code they are not kept in the tarball.

Could be related to https://github.com/ansible/ansible/blob/99d7f150873011e7515851db9b44ff486efa9d77/lib/ansible/galaxy/collection.py#L763

This was noticed as I had some auxiliary scripts in my repo.

Need to also consider scripts in `files/` if/when Collections support roles.

This seems to fail the "principal of least suprise"

**Proposal 1: Keep on stripping executable flags**

Add some line to the output
`WARNING: tests/coverage.sh: source file has executable flag, though this will be ignored in generated tar.gz`
Update developing a collection documentation page
Update integration tests to ensure that executable mode is always stripped.
Update code to link to this issue

**Proposal 2: Allow executible flags**

Update developing a collection documentation page
Update integration tests to ensure that executable mode is preserved
Update code to link to this issue
Changelog


##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
ansible-galaxy

##### ANSIBLE VERSION
```paste below
2.10
```

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can paste gist.github.com links for larger files -->


expected_role_dirs = ('defaults', 'files', 'handlers', 'meta', 'tasks', 'templates', 'vars', 'tests')
    @classmethod
    def setUpRole(cls, role_name, galaxy_args=None, skeleton_path=None, use_explicit_type=False):
        if galaxy_args is None:
            galaxy_args = []
        if skeleton_path is not None:
            cls.role_skeleton_path = skeleton_path
            galaxy_args += ['--role-skeleton', skeleton_path]
        
        cls.test_dir = tempfile.mkdtemp()
        if not os.path.isdir(cls.test_dir):
            os.makedirs(cls.test_dir)
        cls.role_dir = os.path.join(cls.test_dir, role_name)
        cls.role_name = role_name
        
        args = ['ansible-galaxy']
        if use_explicit_type:
            args += ['role']
        args += ['init', '-c', '--offline'] + galaxy_args + ['--init-path', cls.test_dir, cls.role_name]
        gc = GalaxyCLI(args=args)
        gc.run()
        cls.gc = gc
        if skeleton_path is None:
            cls.role_skeleton_path = gc.galaxy.default_role_skeleton_path
    @classmethod
    def tearDownClass(cls):