WIP: Add user configurable keybind to restart the overlay

[Gee19]

Description

This PR adds a user configurable keybind to restart the overlay.

This was something I was looking for (as well as a few other small things like my comment in #85) so why not give it a shot and get more familiar with the repo at the same time. Apologies if I am missing anything obvious, I am open to feedback from anyone.

Bonus:

• Show keybind in context menu when clicking system icon

How Has This Been Tested?

• ran npm run ng:lint
• ran npm run format
• ran npm run ng:test
• added unit tests
• manually tested

Resources:
https://www.electronjs.org/docs/api/app#apprelaunchoptions

[WhiteFang5]

The Show keybind in context menu when clicking system icon? todo might be interesting, and could also be applied to other context menu items (such as quit and settings). I don't deem this necessary to accept the PR though.

However, there is one other thing I do deem necessary and that's the UI addition to allow users to change this keybind and/or properly enable/disable it. (Take a look at user-settings-form.component.html for this)