Add general ability to disable formats within squire

[natejenkins]

We already do this within Authorea, but we need to run parallel disabling within squire itself to prevent unwanted html from being created with keyboard shortcuts (which are set in squire).

see https://github.com/natejenkins/socialApp/issues/3166

[DZGoldman]

It occurs to me that this will actually require to squire have access to state of the authorea app; (for example, some keyboard shortcuts need to be disabled when the title block is active.) Something we don't currently do and it feels anti-pattern, but seems to me to be unavoidable.