Migrate to Pinia stores

[devmount]

Is your feature request related to a problem? Please describe.
Currently, options are stored with vanilla local storage. Which is fine, but not very easy to maintain or extend.

Describe the solution you'd like
Use Pinia store for

• add-on options
• filter values
• stats store

Describe alternatives you've considered
There are a lot of store solutions. Pinia is easy to use.

Additional context
https://pinia.vuejs.org/