OpenWRT package for C implementation of sshnpd

[cpswan]

Is your feature request related to a problem? Please describe.

One of the primary drivers for the C implementation is the small footprint needed by customers asking for NoPorts on OpenWRT devices.

Describe the solution you'd like

A package that works with OpenWRT 23.05 across a broad range of system architectures (e.g. armv7, armv8, mipsel)

Describe alternatives you've considered

It's likely that there will be demand for older versions of OpenWRT where customers have their own distributions based on them. We should approach those on a case by case basis to determine the footprint, architecture and preferred TLS implementation.

Additional context

Whilst we can run the Python sshnpd on OpenWRT there's generally insufficient storage for all of the dependencies (~100MB).

atsign-foundation/noports#633

atsign-foundation/noports#670

[cpswan]

https://github.com/atsign-foundation/Atsign_OpenWRT_packages/tree/cpswan-hello-cmake branch contains an example Cmake app

[cpswan]

C sshnpd wasn't ready for packaging in PR81. Bumping to PR82

[cpswan]

C sshnpd wasn't ready for packaging in PR82. Bumping to PR83