Add optional reply-to support to tag command

[DevSerendipity]

Adds the optional support to /tag to reply-to users, they will then be mentioned:

This implements and closes #276 .

[CLAassistant]

All committers have signed the CLA.

[DevSerendipity]

Could someone explain to me why we can't use

mentionUserOption.getAsMember().getAsMention() which gives no warnings opposite to

mentionUserOption.getAsUser().getAsMention()

[Zabuzard]

This cant be merged with the current git history. For some reason it has commits in it that shouldnt belong in here (for example a commit by Yusuf adding the warn command). Please rebase on develop and clean up your history so that it only has the changes that you actually made in this PR and nothing else.

In the worst case, just reset-mixed and then create a new commit with the now-reset changes.

[DevSerendipity]

This cant be merged with the current git history. For some reason it has commits in it that shouldnt belong in here (for example a commit by Yusuf adding the warn command). Please rebase on develop and clean up your history so that it only has the changes that you actually made in this PR and nothing else.

In the worst case, just reset-mixed and then create a new commit with the now-reset changes.

The problem started when I pulled all the changes from my fork and rebased the origin developer branch. I wanted to resolve the merge conflict 2 days ago and when i pulled all those changes, i forgot that it pulled it to my feature/command-reply user branch and commited it.

Yesterday I tried with @Tais993 to roleback commits since i pushed all those changes, and it didn't sadly work.

done