* [WIP][docker_container] Adding support for `mounts` option
Fixes#42054
* Adjusting to current standards.
* Add changelog.
* Adjust types.
* Cleanup.
* Add idempotency checks for mounts.
* Improve diff for mounts.
* Linting.
* Python 2.6 compatibility.
* Fix error message formatting.
* Move mounts and volumes tests into own file.
* Add set of mount tests.
* Golang's omitempty for bool omits false values.
* Simplify sanity checks. Correct order of volume_options sanitization and usage.
* Fix key.
* Fix check.
* Add tests where both volumes and mounts show up.
* Add collision test.
