Add keyboard shortcut for rescanning

[tkohlmeier]

This adds F5 as a keyboard shortcut for rescanning. I think it is much more convenient than having to enter rescan.

[tkohlmeier]

Added an entry for the hotkey to the settings:

Do you think this should be editable or platform-specific?

Also improved some translations.

[oliverschwendener]

Here are a few thoughts:

• I don't think that typing "rescan" is so unintuitive that it needs a keyboard shortcut. If you have to do a rescan very often, consider lowering the rescan interval or mark the "rescan extensions" search result as a favorite, then it shows up higher in the search results. Then, maybe you just have to enter "re" and press enter.
• "F5" is very Windowsy, please suggest appropriate keyboard shortcuts for the other platforms
• Be careful with the term "hotkey". I consider the "hotkey" to be the keyboard shortcut that can be pressed outside of the app. Keyboard shortcuts inside of the app I call "keyboard shortcuts". I suggest to rename the "hotkey" in this context to "keyboard shortcut".

[tkohlmeier]

• I didn't say it's unintuitive, but inconvenient. Ueli 8 had this keyboard shortcut and I used it whenever I installed new software or created new application shortcuts. I don't have automatic rescan enabled since it uses too much resources IMO. Furthermore, why do we have a shortcut for the settings? You can open the settings by searching for "Open Ueli settings` as well, but shortcuts are more convenient.
• Firefox shortcuts for reload:
  Windows/Linux: F5 or CtrlR
  Mac: F5 or CmdR
  The problem with CtrlR is, that this collides with the Electron reload function. If we disable the menu in the packaged version, the Electron shortcut should not be present anymore.
• OK, for me those terms were synonymous. If you agree to this feature in general I will adjust it.

[oliverschwendener]

Ok also fair enough :)

What do you think about the following?

• Let's use F5 for all platforms to not collide with electron's refresh keyboard shortcut
• Let's call it "Keyboard shortcut" in the settings so the term "hotkey" is used solely for the "global hotkey"

[tkohlmeier]

Sounds good. Just one thing about Electron's refresh function: When we remove the menu in #1327, this shortcut won't be available anymore.