##### 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 -->


files_manifest_json = to_bytes(json.dumps(file_manifest, indent=True), errors='surrogate_or_strict')
    collection_manifest['file_manifest_file']['chksum_sha256'] = secure_hash_s(files_manifest_json, hash_func=sha256)
    collection_manifest_json = to_bytes(json.dumps(collection_manifest, indent=True), errors='surrogate_or_strict')
    with _tempdir() as b_temp_path:
        b_tar_filepath = os.path.join(b_temp_path, os.path.basename(b_tar_path))
        with tarfile.open(b_tar_filepath, mode='w:gz') as tar_file:
            
            for name, b in [('MANIFEST.json', collection_manifest_json), ('FILES.json', files_manifest_json)]:
                b_io = BytesIO(b)
                tar_info = tarfile.TarInfo(name)
                tar_info.size = len(b)
                tar_info.mtime = time.time()
                tar_info.mode = 0o0644
                tar_file.addfile(tarinfo=tar_info, fileobj=b_io)
            for file_info in file_manifest['files']:
                if file_info['name'] == '.':
                    continue
                
                filename = to_native(file_info['name'], errors='surrogate_or_strict')
                b_src_path = os.path.join(b_collection_path, to_bytes(filename, errors='surrogate_or_strict'))
                def reset_stat(tarinfo):