Cache sysinfo data, and only query for the data we actually use

[nightkr]

Description

Fixes #19. There's still room for improvement, but on my desktop this takes us from ~50MiB on startup and ~95MiB steady state, to ~8MiB steady state.

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

Preview Give feedback

No tasks being tracked yet.

Reviewer

Preview Give feedback

1. Code contains useful comments
2. (Integration-)Test cases added
3. Documentation added or updated
4. Changelog updated
5. Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

Preview Give feedback

1. Feature Tracker has been updated
2. Proper release label has been added

[razvan]

indeed, weird api but it works