Added Button to Reset Settings in SettingScreen

[SanjaySargam]

Fixes #447

Screen Recording

reset.mp4

[SebaDro]

Hi @SanjaySargam . Many thanks for your contribution. I like the new resetting feature since it increases user experience and users won't have to reset every single setting. However, I'd suggest following improvements before considering it for merge:

1. The button is not highlighted enough, so users may oversee it. Please, check the style of other UI controls in the app and use the same for the reset button.
2. I think the button should be moved to the bottom of the screen. It feels a little bit misplaced in the top. Maybe, implement sticky behaviour, but I'm not sure about and open for suggestions about the right place.
3. Before applying a reset the user should be asked again, if he is sure about it. Just show a MaterialAlertDialog, which asks the user about it. Please, also have a look how other Dialogs are styled and implemented in the app and adopt it for your one.

What do you think about it? Will you work on it?

[SanjaySargam]

What do you think about it? Will you work on it?

@SebaDro Yeah Sure. I'll work on it