debian packaged server plugins should install/remove without server restart

When installing server plugins, it should be possible to do (SQL `install plugin`) without restarting a server on plugins that need no options.

A user shouldn't need to take downtime to install a plugin.

Likewise plugins should be able to be removed. Need to check if they are in use somehow, but otherwise it should be possible to remove without restart.

e.g:

• spider
• s3 (if variables are global and not read only)
• connect
• rocksdb
• columnstore
• oqgraph
• mroonga
• sphinx
• gssapi (is that a server or client plugin??)