add openwrt builds to CI pipeline

[majestrate]

Like we do with debian package branches we should also provide an OpenWRT branch for CI.

We already have a branch for this laying about that we can revive.

The following subtasks for this are:

• ensure we can Compile Lokinet with the OpenWRT SDK's cmake toolchain
• make docker images for CI that compile lokinet with OpenWRT's SDK
• review and optionally revise the existing OpenWRT system layer shims and configs