mgr/dashboard: replace string version with class

mgr/dashboard: replace string version with class

* APIVersion:
  * Moved to a separate file
  * Added doctests
  * Added sentinel values:
    * DEFAULT = 1.0
    * EXPERIMENTAL = 0.1
    * NONE = 0.0
  * Added to_mime_type() helper method
* Controllers.__init__:
  * Added type hints
  * Replaced string versions with APIVersions
* Feedback controller:
  * Replaced with EXPERIMENTAL (probably it should be NONE)

Fixes: https://tracker.ceph.com/issues/52480
Signed-off-by: Ernesto Puerta <epuertat@redhat.com>
 Conflicts:
	src/pybind/mgr/dashboard/controllers/__init__.py
   - Remove the current changes and keep the incoming new changes
	src/pybind/mgr/dashboard/controllers/crush_rule.py
   - Changes related to the versioning like importing the APIVersion
	src/pybind/mgr/dashboard/controllers/docs.py
   - Changes related to the versioning like importing the APIVersion
	src/pybind/mgr/dashboard/controllers/feedback.py
   - Deleted the file since feedback module isn't backported to pacific
	src/pybind/mgr/dashboard/controllers/host.py
   - Changes related to the versioning like importing the APIVersion
	src/pybind/mgr/dashboard/openapi.yaml
   - Generated a new openapi yaml file
	src/pybind/mgr/dashboard/tests/__init__.py
   - Changes related to the versioning like importing the APIVersion
	src/pybind/mgr/dashboard/tests/test_docs.py
   - Changes related to the versioning like importing the APIVersion
	src/pybind/mgr/dashboard/tests/test_host.py
   - Changes related to the versioning like importing the APIVersion
	src/pybind/mgr/dashboard/tests/test_tools.py
   - Changes related to the versioning like importing the APIVersion
	src/pybind/mgr/dashboard/tests/test_versioning.py
   - Changes related to the versioning like importing the APIVersion
	src/pybind/mgr/dashboard/controllers/crush_rule.py
   - Removed the MethodMap decorator which updates the version of the
     enpoint to 2.0 because those changes which caused that version
     updating were not backported to pacific