New layout format and User data migration capability!

[mominul]

Here I present version 2 of the keyboard method layout format of OBK version 2! 🎉

This layout format uses Zstandard compression algorithm for compressing the images and uses a custom variant of Base91 for decoding the binary bytes into textual format. Base91 is 6% more efficient than Base64 which we currently use. As a result, the layout files we distribute altogether have their sizes shrunken to 58% 🎉

With the new layout format, we now support system keyboard layout other than Qwerty(#36) without any hackery in the parser and with additional number keys. I have also added a heavy test for the parser which will prevent further typo bugs(#98) from happening.

I have also changed the names of two layouts:

• Bornona to Borno. (This was the real name, I don't know why Avro team had changed it.).
• Munir Optima (uni) to Munir Optima.

This PR also adds User data migration capability to OBK. It also includes a converter for the new format. So the next release of OBK will be no longer a breaking version. 🎉

[mominul]

cc @Adyel @bdeshi

[mominul]

Opened a new PR #143 because of the conflicting submodule change.