Expand /tag-Command to accept arrays

Expand the `/tag`-command by making it possible to pass an array of tags.

The idea is that you can add and remove tags like this:

/tag @p add [foo,bar,baz]
/tag @p remove [bar,baz,foo]

or for better readability like this:

/tag @p add [foo, bar, baz]
/tag @p remove [baz, bar, foo]

or still like the old way:

/tag @p add foo
/tag @p add bar
/tag @p remove bar
/tag @p remove foo

Whether the new or old syntax will be used can depend on whether the argument starts with a square bracket. This should be easily possible because of the current syntax of the `/tag`-command doesn't allows square bracktes or commas.

Why is it a nice addition?
Sometimes you want to give a very specific entity multiple tags. In this scenario you currently need run multiple commands, partially with long `/execute` commands and selectors. In this case it would be very nice, if you could run just one command which adds all commands at the same time.