feat(minimessage): named arguments

[Strokkur424]

closes #1296.

[Strokkur424]

I've rebased the PR to the unstable/4 branch so that I can do some work for the upcoming head tag with the changes introduced here already.

[Strokkur424]

Rebased to main/4 after the unstable/4 merge

[zml2008]

So a thought on this, why are we creating two different colours of MM tags? I feel like the design would be cleaner if we only had one type of tag, which accepted both named and sequential arguments, same as say with a CLI. For consistency's sake I think it's fair to require all the named args to be at the beginning or end of the tag, but either way there's a bunch of api noise and opportunity for breakages here due to adding named args in as a separate parallel concept.

I'm seeing something like:

<gradient phase=0.4 speed=2 red:green:blue>hi strokkur</gradient>

or:

<gradient:red:green:blue phase=0.4 speed=2>hi strokkur</gradient>

What do you think? Users would just pop named args from the ArgumentQueue same as other items

[Strokkur424]

Alright, I've done everything I've wanted to do for this PR now. Arguments have been implemented, as per @zml2008's suggestion, in a combined way. They new syntax looks like this:

<tagname
    someflag
    somename='a quoted value with spaces'
    anotherflag :queued arguments behind:here>Hey abby</tagname>

This means named arguments are simply placed between the tag name and the first colon.