Images, colors, pdf export & more

[Ethran]

List of changes:

• Add images to database
• fixed crash on pdf export,
• it now shows error on jpg and png export instead of crashing
• set width of exported page to width of A4 paper issue exporting to A4 format #20
• fixed issue No Writing on Note Air 4C #45 and No writing on Boox Note Air 3C? #34 by updating to newer onyx sdk
• colors were added by add color? #26, thanks to work by @alokehpdev
• removed pencil and other "NeoTools" as they caused crushes
• add basic support for images: adding images, selecting and moving them on canvas
• add covers for notebooks
• notebooks respect "default page background template" setting
• changed marker behavior
• changes fountain pen -- now it is not depended on onyx sdk for drawing on canvas
• improved gestures: double tap should be recognize better, on two finger touch now have small tolerance for movent of fingers
• added hold gesture for selecting images
• moved function handling selection to select.kt
• added support for drawing lines,
• fixed refresh after undo, it is still not perfect but slightly better
• changed icon for library to home
• fixed issues with undo not working on most recent stroke
• issue maintain a list of supported devices e.g. as part of the readme.md #43 , PR list of supported devices #44 added to readme
• fixed sharing of selection

Sorry for not splitting this into smaller fixes, but I noticed there hasn't been much development on this repo, so I made improvements on my own to better fit my needs. I can confirm that it works on the Boox Note Air 4C running Android 13. I will periodically add changes and improvements to my fork, likely small adjustments to address things that annoy me while using the app (as with the changes mentioned above).