Feature/314 mini players without playlist (#670)

* Adds a translation string

* Adds a switch player button

* Adds empty components for cover and mini players

* Adds PlayerSwitcherService

* Attempts to store player settings individually

* Revert "Attempts to store player settings individually"

This reverts commit 6f9fb8e.

* Sends toggle player signals from renderer to main

* Starts building player switching

* Changes positioning and resizing of main window

* Improves initial positioning of window

* Splits off switch player button

* Improves cover player window

* Aligns content

* Improves window controls

* Improves window buttons

* Adds playback information to cover player

* Fixes maximize behavior

* Fixes cover player height when using native title bar

* Adds bottom sheets for playback queue and volume control

* Adds switch player button to now playing screen

* Removes padding from bottom sheet

* Fixes setting of initial window size

* Adds playback queue to cover player

* Fixes unit tests