Support filtering on Mojeek

[SnorlaxMonster]

Add support for the search engine Mojeek.

Due to Mojeek having some fairly generic selectors on their CSS rules, I've explicitly specified some default properties on the replacement button to prevent the button from being re-styled.

Additionally, due to how Mojeek search results are structured, having the replacement notice displayed as display: inline-block caused the original URL to be placed inline with the replacement notice. I've changed it to display: block instead, and this appears to look the same as before on other search engines.

I'm matching the site as https://*.mojeek.com/*, although the only subdomain I've actually seen is https://www.mojeek.com

[KevinPayravi]

Thank you for this!

I'm putting the addition of new search engines on-hold until we can get the permissions to be opt-in. Reason is that new domain permissions require a manual approval by the user to update, which causes a large drop-off in users who keep the extension p-to-date (and raises concerns from users who see IWB requesting access to sites unknown to them).

I had previously tried to make search engine permissions opt-in by registering the search engine filtering content per-domain when the user enables a search engine. The issue there is that content scripts are de-registers whenever the extension is updated. One potential solution is to still do all that, but set up additional logic to re-register content scripts whenever the extension updates (or whenever it otherwise detects that the content script has been de-registered).

[SnorlaxMonster]

That makes sense. If the extension did not require access to every supported search engine, that would be a much better user experience.