WIP: DUNE/Parsers/APConfig: added skeleton of parser for Ardupilot config

[krisgry]

As mentioned in our previous dev call, we have made a parser for Ardupilot configuration files. It is essentially a simplified version of the existing DUNE/Parsers/Config parser.

It has been tested, but not extensively.

Known limitations:

• AP config files allow both space and comma as separator between the parameter name and value. This only supports space for now
• Have not added support for setting/getting a single parameter, as our use-case was to read a set of parameters from a file and treat these as a whole. We used the update function to update the whole parameter list if the parameter file path was changed.

I don't think this should be merged in its current state, but I put it here if someone is interested in continuing this work (as I don't see myself continuing down this path in the immediate future).

Open for comments/questions, for future reference :)