Create copy for 2 moderation scenarios

[miketaylr]

We need text to cover 2 scenarios:

A pre-moderation message: something like, thanks for reporting an issue you can check back here once it's been moderated and made public.

A post-moderation rejection message: this report doesn't follow our acceptable use guidelines.

Note we don't have acceptable use guidelines, so it probably has to be more generic, or we adopt or hack Mozilla's: https://www.mozilla.org/en-US/about/legal/acceptable-use/

[karlcow]

In Quarantine

<p>This issue has been put in quarantine. A human
will review if the message meets our current 
<a href="/acceptable-use">acceptable use</a> guidelines. 
It will probably take a couple of days depending on the backlog.
Once it has been reviewed, the content will be either made public
or deleted.</p>

Rejected Message

<p>The content of this issue doesn't meet our 
<a href="/acceptable-use">acceptable use</a>
guidelines. Its original content has been deleted.</p>

About the thanks.

As this is a generic message, I don't think the thanks should be part of the content.

[karlcow]

Dependencies on #3143 and #3138

[miketaylr]

I like the proposals, but I think the word quarantine has dramatic semantic connotations. I would recommend we just use "moderation".

[karlcow]

s/in quarantine./in the moderation queue./

[miketaylr]

(assigning to karl, since he did the work. we can probably just close this when #3150 is merged)