[Warnings] Add setting for warn channel and DMing warns toggle

[Ianardo-DiCaprio]

Type

• Bugfix
• Enhancement
• New feature

Description of the changes

This adds commands requested in #2800. It allows to toggle warns being sent to DM's, allows to toggle warns being sent to a channel on a server and has a command to set the channel the warns get sent to, if no channel is set it gets sent to the channel the [p]warn command was used in.

[DevilXD]

Just couple of changes.

Also, from the original issue:

(...) option to warn a user (i.e. ping them) in set guild channel and/or just warn that user in channel where the [p]warn command was issued.

This could be slightly hard to understand, at least for me. I've commented on the original issue, but basically - there already is an option to log warnings into the modlog channel. A second channel with warnings only could be made public tho, so I guess there is some logic behind having it like this ¯\_(ツ)_/¯

[Jackenmen]

Looks good, I know it looks like a lot of review comments, but these are all just minor string improvements =)

[Jackenmen]

One thing I didn't notice in first review.
Once this and UX stuff pointed out by Draper gets handled, this should be ready to go.

[FixedThink]

Would it be possible to inform the author about the DM not being sent if it's enabled?
If the DM fails, the kick/ban will still succeed, but the bot will send a message like "This user did not receive your case as they have either blocked the bot or disabled DMs." I think this will be much better then just sending a DM without any sort of feedback as of what happened to it.

The reason for this is that (to me at least) it tends to happen that someone says they have never been informed about why they're kicked/muted/whatever, but that there is no way for a staff member to actually verify whether that's true or whether they're 🙈. In other words it would ease a lot of moderation arguments and such, especially with warnings.

[Jackenmen]

@FixedThink It would be possible but in my opinion this shouldn't be part of this PR, I would advice making a separate issue with a request for this enhancement.

[Jackenmen]

This should be the only needed change before this can be approved.