make display-messages lsp config true by default

[adsick]

This guides how to turn on lsp status messages, but one may have a wrong workspace setup, lsp will produce errors and user won't see them which is bad.

[matoous]

I would say display-messages is too verbose for it to be on by default. Maybe the config could have severity value instead (error, warn, info) and only filtered messages could be displayed.

[adsick]

Kinda agree but still think that the messages are useful so it is better to see them than not to see.