Convert docstrings & switch docs puplishing

[wm-wm-wm]

Change Summary

Convert docstrings from RST to markdown & switch docs puplishing from sphinx to mkdocs

Related issue number

[DOP-37884]

Checklist

• Commit message and PR title is comprehensive
• Keep the change as small as possible
• Unit and integration tests for the changes exist
• Tests pass on CI and coverage does not decrease
• Documentation reflects the changes where applicable
• docs/changelog/next_release/<pull request or issue id>.<change type>.rst file added describing change
  (see CONTRIBUTING.rst for details.)
• My PR is ready to review.

[github-actions]

Coverage Report •

File	Stmts	Miss	Branch	BrPart	Cover	Missing
data_rentgen/consumer/settings
consumer.py	28	4	4	2	81%	39->40, 40–41, 42->43, 43–44
kafka.py	29	4	4	3	79%	21, 86->88, 88–90
data_rentgen/consumer/settings/security
gssapi.py	79	48	16	16	33%	58–64, 67, 70, 76–77, 79, 86–90, 93–95, 97–100, 103–104, 106–109, 112–113, 115–118, 121–124, 127–128, 130, 132–133, 135, 138–139
plain.py	10	1	0	0	90%	30
scram.py	16	1	0	0	94%	54
data_rentgen/dependencies
stub.py	16	3	6	2	77%	32->34, 34, 37->39, 39, 43
data_rentgen/exceptions
auth.py	32	6	0	0	81%	28, 32, 44, 48, 71, 75
entity.py	30	4	0	0	87%	38, 42, 79, 83
data_rentgen/openlineage/run_facets
airflow.py	48	2	4	0	96%	45, 110
data_rentgen/server/settings
cors.py	19	5	4	4	61%	63–67
session.py	21	2	2	1	87%	80->81, 81–82
static_files.py	14	7	4	4	39%	31–37
data_rentgen/server/settings/auth
__init__.py	14	2	2	1	81%	42->43, 43–44
personal_token.py	17	2	2	1	84%	74->75, 75–76
data_rentgen/utils
uuid.py	47	3	4	2	90%	111->112, 112–113, 114->115, 115
TOTAL	7712	518	1306	211	92%