Backend: Change colour (UK) to color (US)

[hannibal002]

What

For consistency, we change all usages of colour to color.

Only exceptions in this PR:

• @ConfigEditorColour (From MoulConfig)
• Utils.chromaStringByColourCode() (From NotEnoughUpdates)
• Config names (Added To-dos to all of them, might change a ton/all config rename To-dos in a later pr at once)

Without this PR

With this PR

Changelog Technical Details

• Changed "colour" to "color" internally, everywhere. - hannibal2

[Thunderblade73]

Please at that info in the contribution guidelines. So that there can't any confusions in the future.

[nea89o]

Are there any calls on other American vs British language? I still learned British English, so that is what I am used to, even beyond -our vs -or: -ise vs -ize, -ogue vs -og, etc.