burns_[colour] block tag: add all colours of fire via a datapack

###Introduction

The addition of soul fire was great, not just for ambiance in the nether, but also for general decoration purposes and, ever since then, people have wanted more colours of fire (in fact, coloured fire has been a popular suggestion even before that), as seen by the "X should burn [colour]" suggestions.

At the same time, Mojang has been working on moving hardcoded features into data files, the so called datapacks, so that many things can be easily edited both by the Devs and by the players.

Given these two things, we can move on to the suggestion.

###The suggestion

There would now be several new block tags, following the structure burns_[colour], one for each colour, for example burns_red or burns_black.

The colour of the fire block would now depend on the block it's in.

By default, all blocks would have the burns_orange tag, so nothing would change.

This would not affect soul fire, as that's a separate block that generates on blocks with the soul_fire_base_blocks tag.

###Notes

Since it's possible to place a block in multiple of these tags, the colour of the for could be determined in one of two ways:

1. (Not ideal and unintuitive) The first or last tag loaded determines the colour of the fire.

Or

2. (Best and most flexible option) Blocks with multiple of these tags make fire burning on them to cycle between all the colours that apply to that block. So, if you place a block in all these tags, you'll essentially have jeb_ fire :-)

For organisation purposes, these tags could instead be grouped into a fire_colour folder, changing burns_green to fire_colour/green, for example.

Tell me what you think of this idea. Is there something I overlooked?