Dashboard configuration: Hide query bar option

[alexfrancoeur]

The query bar is shown in every dashboard by default. As we begin to offer more limited read-only views, I'm not sure it makes sense for everyone to always have access to query bar. It is possible that a non-performant query may affect the performance of a cluster. If you are not familiar / comfortable with query syntax or simply want to save additional space on the dashboard we could offer the option to hide the query bar in view mode when configuring a dashboard. With the introduction of input controls we will be able to curate a dashboard only users experience a bit more.

cc: @elastic/kibana-sharing

[Heenawter]

Closing in favour of #137560, since that's a bit more up-to-date and has some good discussion 👍