Partially added boss Bringer of Death

See merge request !37

Added close to complete skeleton boss

See merge request !36

Merge branch 'main' of https://gitlab.stud.idi.ntnu.no/gardaf/mr-bigsock into JuliusesNyeSuperBranch

Massive rework of inventory system.

See merge request !35

- Now has 4 sections.
- Made to support the new inventory design.
- Passive items now only affect player if added to specific sections.
- All sections have their full size, null indicates a slot is empty.
- Functionality to easily move items between sections.
- Much more convoluted back-end code.
- It just works now.

Dodge

See merge request !34