Building of osrm-backend is not working

Close for LL 12.1.0

Yes

Given it seems the project ended up not needing the osrm bits on target, nothing in the demo images use them, and they currently do not build, I propose repurposing this issue to remove the recipes from meta-agl-demo.  @Jan-Simon Moeller and/or @Walt Miner, does that seem reasonable?

@Thomas Walzer, can you or Sebastian provide some feedback on your plans wrt osrm?  If there is some intent to upstream code to agl-service-navigation or elsewhere, I'd somewhat prefer it be based on the library versus a bunch of extra JSON parsing on top of libcurl.

So I have recipe updates for osmium, protozero, and osrm-backend in hand (devtool upgrade yielded mostly-working recipes).  The issues that remain are:

• The pkg-config file that gets generated by the osrm-backend build is not really usable and I won't be able to easily test if I hack on the source CMakeLists.txt to try to fix it.  This might not be a problem if you're okay with just coding up explicitly specifying -losrm in your Makefiles or the like for whatever it is you're planning to build.  Please let me know.

• AFAICT it is the case that osrm-backend only generates static libraries.  If you plan to build your applications with the SDK, the staticdev package will need to explicitly be added to the SDK for that to work.  Please confirm if that's your plan, as I'd not do it otherwise to avoid unnecessarily bloating the SDK.

• osrm-backend is relying on a packaged copy of flatbuffers that I've not managed to pull apart to use a system version.  This isn't a blocker, but is less than ideal and more investigation will likely be required if a situation comes up where the upstream AGL demo images need to include something that uses libosrm.