Add support for HOSTNAME diagnostics message

[DL6ER]

By submitting this pull request, I confirm the following:

• I have read and understood the contributors guide, as well as this entire template.
• I have made only one major change in my proposed changes.
• I have commented my proposed changes within the code.
• I have tested my proposed changes, and have included unit tests where possible.
• I am willing to help maintain this change if there are issues with it later.
• I give this submission freely and claim no ownership.
• It is compatible with the EUPL 1.2 license
• I have squashed any insignificant commits. (git rebase)

---

What does this PR aim to accomplish?:

Add host name error messages/warnings to the Pi-hole diagnostics system

How does this PR accomplish the above?:

Add front end support for pi-hole/FTL#780

What documentation changes (if any) are needed to support this PR?:

None

[DL6ER]

IE compatibility should be restored + the branch is rebased onto latest devel.

[XhmikosR]

I don't see why this can't work?

for (var i = 0; i < row.blob2 + row.message.length + 2; i++) {
  hint += " ";
}

[PromoFaux]

Just chucking this in the ring:

var hint = new Array(row.blob2 + row.message.length + 3).join(" ");

[DL6ER]

@XhmikosR This works as well, however, it is really verbose for a very simple task. It adheres to our style criteria and is ready to merge IMO. @PromoFaux We can use this as well, can you commit/ppush it?

It is also worth pointing out that the failed node tests do not have to do with the changes in this PR.

[XhmikosR]

I honestly don't see how it's more verbose... I mean, the whole codebase is verbose :P

Anyway, prettier will go away soon.

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/pi-hole-5-1-released/35577/1