feat: implement group system

[iMeaNz]

Objective

Inspired by EnTT, we should have a group system.
This group system would allow the user to "bind" several components together.
The component arrays of those components will then get rearranged so that every entities components of entities owning all the component would be put at the beginning of the component array, allowing for a very fast iteration when updating.

Acceptance Criteria

• 1. Refactor the component array to be able to easily re-arrange the data layout
• 2. Implement a group class handling the group itself
• 3. Add API method to create/delete/get a group

Dependencies

No response

Technical Details

No response

Type

Engine

[iMeaNz]

Done.
See #171 (comment) for more info

Ready for review