Add Fencing Testbox v0.1

[aarjaneiro]

Application Submission

An app replicating the functionality of a fencing testbox (a commonly-used tool in the sport of fencing to test the functionality of blades and body wires).

Extra Requirements

A fencing body wire (perhaps connected to a fencing foil/epee/sabre) is required and should be connected to the gpio pins as specified under the Wiring submenu option in-app.

Author Checklist (Fill this out)

• [x] I've read the contribution guidelines and my PR follows them
• [x] I own the code I'm submitting or have code owner's permission to submit it
• [x] I have validated the manifest file(s) with python3 tools/bundle.py --nolint applications/CATEGORY/APPID/manifest.yml bundle.zip

Reviewer Checklist (Don't fill this out)

• [x] Bundle is valid
• [x] There are no obvious issues with the source code
• [x] I've ran this application and verified its functionality