Clean up lspclient actions to reduce visual clutter

In my opinion Kate has too many options visible at first glance, especially in LSPClient menu actions. So I decided to remove some of them, that didn't make sense to me to be so easily accessible.

Removed actions that aren't accessible otherwise:

• "Hover" - it doesn't seem intuitive to activate an on-hover behaviour by going to the menu bar :D And it is noted in the comments inside the code too. So either it should be renamed to what it really means(whatever that is) or removed imo.

Removed actions that are accessible from the LSPClient settings panel(generally the toggle buttons):

• "Show selected completion documentation"
• "Include declaration in references"
• "Show hover information"
• "Format on typing"
• "Incremental document synchronization"
• "Show diagnostics notifications"
• "Show diagnostics highlights"
• "Show diagnostics marks"
• "Show diagnostics on hover"
• "Show messages"
• "Switch to messages tab upon message level >"

I didn't want to remove any code that handles those actions yet because I wanted to know first if other Kate developers agree with such a change. So what do you think? It's a huge improvement for me, especially on my 1366x768 screen where these buttons take almost the entire screen height, while I am never even tempted to use them.