Android support and CI

[robinhundt]

I just found the dinghy tool which allows really easy cross testing support. After a quick change to enable the bindgen feature of aws-lc-rs, SEEC compiled for my aarch64-linux-android phone and all tests passed.
We should expose this feature in seec-channel/seec and run our testsuite on Android ARM in CI. For this, we can either use cargo-dinghy or the cross tool which might require even less setup as it automatically uses QEMU to emulate the target environment.