Add [!] Error status

[P3run]

Changes:

1. Introduced a new status: [!] Error.
2. Changed the colour of [x] Rate Limit to yellow as [!] Error is now red.
3. [!] Error is now returned by default if not set otherwise in the module.
4. The "error" flag in the result object is optional so it is not necessary to update existing modules and set it to False.

[mark-sercombe]

Great! I will hopefully start implementing it in the modules soon

[P3run]

Oh, I think that @megadose needs to approve and merge it first. That's why I haven't touched my other pull requests yet.