Ceph Dashboard Developer Documentation

Note: The content of this file has been moved into the Ceph Developer Guide.

If you're interested in helping with the development of the dashboard, please see /doc/dev/developer_guide/dash-devel.rst or the online version <https://ceph.readthedocs.io/en/latest/dev/developer_guide/dash-devel/>_ for details on how to set up a development environment and other development-related topics.