Migrate docs/user/info/cli.rst to Markdown
When running the documentation Makefile we get the following error:
[E 231101 20:32:58 server:94] b"/workspace/funkwhale/docs/index.md:7: WARNING: toctree contains reference to nonexisting document 'user/info/cli'\n"
The reason is that docs/user/info/cli.rst
is not yet migrated to Markdown