Format LetsEncrypt output display/error messages

The output of the Lescript.php vendor lib currently goes unfiltered to stdout, resulting in an almost unreadable unformatted display:
Existing successful letsencrypt results:

Existing failed letsencrypt results:

Pull request captures the output, and parses the LetsEncrypt json for a valid error message. To keep the display clean, the details are hidden in a collapsed div unless requested via a hover:
New successful results:
Collapsed

Expanded

New failed results:
Collapsed

Expanded

I'd been sitting on this for a while, posting now because I doubt I will proceed further unless I decide to finish dns-01 auth.

It's worth merging as is IMO, and gives the module a more polished look. The structure is sound. The html alert code works, but is a bit of a cut and paste mess of existing elements to achieve the desired effect. I had intended to properly implement with new css/js but doubt I will get to it at this point.