Move dependencies into their own repos / connect with submodules

[Moneyl]

Dependencies should be moved into their own repos so this repo only contains it's own code, and stays small.

Ideally all dependencies would be connected via submodules and rebuilt for each build. However, this might negatively impact build times. One option is to keep including all or some dependencies prebuilt, but to place them into a submodule. Something in between the two is probably best.