Update to upstream version 2.1.0 to enable sx1303 support.

[n5qm]

The goal of this PR is to update the codebase to the upstream v2.1.0 prompted by gaining support for the sx1303 concentrator variant which is found in the Senscap hotspots and to enable the use of the sx1303 concentrator by others.

I have accomplished the following thus far:

• ported the timestamp fix
• disabled the GPS by default in the configuration files
• updated the configuration files to use the com_type and com_path configuration directives
• updated the configuration files to use the fine_timestamp configuration directives instead of precision_timestamp
• general configuration file work to make them consistent
• created a Dockerfile and entrypoint script for the packet forwarder

I am currently testing this on one of my units and have not yet identified any obvious issues, but more testing is likely needed.

If you can provide some guidance on what other changes should be completed to enable these changes to be used I am interested in continuing the work so it can be used by everyone.

[shawaj]

Take a look at our hm-pktfwd as well for reference https://github.com/NebraLtd/hm-pktfwd