feat: Improve UI/UX of the "Select source" screen

[brosssh]

Feature description

It should be agreed on a better design of the "Select source" screen. There are few issues with it, linked as sub issues to this one.

Motivation

Currently the "Select source" screen before a patching process is confusing and lack UI.

Acknowledgements

• I have checked all open and closed feature requests and this is not a duplicate.
• I have chosen an appropriate title.
• The feature request is only related to ReVanced Manager.

[brosssh]

Could a design be agreed for this screen?
@validcube @Ushie @PalmDevs

[Ushie]

This is a bit difficult, since the user interaction flow hasn't been revisited after downloaders were added, they were a bit of a slap on feat

Part of this issue should be pursuing a more friendly UX including the flow