Improve file size of output from DrawingFragment

https://www.reddit.com/r/Anki/comments/1t1qpzm/does_drawing_picture_instead_of_adding_the_image/

We save the Whiteboard as JPG with quality 95.

https://github.com/ankidroid/Anki-Android/blob/0498bdfd9ab31706f15c1acc71092b4f1a80b365/AnkiDroid/src/main/java/com/ichi2/anki/DrawingFragment.kt#L83-L99

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* [x] Create a few images and see the sizes, determine if this is a problem
* Reported sizes of 300KB on reddit - likely an issue
* See below. Ouch
2. Determine the output file we want
* I suspect we should generate a SVG, since the file should be moved to `collection.media`