Support globs in file permission configuration

[TadCordle]

Original comment

It may be useful to set file permissions in bulk, like so:

jib.extraDirectories.permissions = ['/*.txt':'755', '/**.sh':'555']

<permissions>
  <permission>
    <file>/*.txt</file>
    <mode>755</mode>
  </permission>
  <permission>
    <file>/**.sh</file>
    <mode>555</mode>
  </permission>
</permissions>

[loosebazooka]

I feel like we should do this soon. Adding to milestone 2.2.0