Feature: Create a proper `Inventory` component

[anafro]

Is your feature request related to a problem? Please describe.
The half-working Inventory was poorely designed due to the tight schedule, and was actually a hot-fix solution. Therefore, the Inventory component must be redesigned to somehow interact with the Board (maybe via the v-model).

Describe the solution you'd like
A clear and concise description of what you want to happen.

Additional context
The hot-fix, by the way, must be eliminated from the Thunderlight's codebase.