Add diagnostic daemon

[Nicogene]

This PR add the diagnostidaemon to the ICUB_HEAD profile.

It will be draft(and I think not passing CI) until diagnostic-daemon won't be public

[Nicogene]

@traversaro the build of macOS is failing due to :

/diagnosticdaemon.build/Release/diagnosticdaemon.build/Objects-normal/x86_64/diagnosticdaemon_dependency_info.dat -o /Users/runner/work/robotology-superbuild/robotology-superbuild/build/robotology/diagnosticdaemon/Release/diagnosticdaemon
2020-07-28T12:51:20.1520890Z ld: library not found for -lstdc++fs
2020-07-28T12:51:20.1521900Z clang: error: linker command failed with exit code 1 (use -v to see invocation)
2020-07-28T12:51:20.1523300Z 
2020-07-28T12:51:20.1555710Z ** BUILD FAILED **
2020-07-28T12:51:20.1557240Z 

I added that library for using <experimental/filesystem> since <filesystem> is available only since gcc 8 and Ubuntu 18.04 has gcc 7.5.

It is possible to add the macOs compatibility but I don't think it would be worthy.
Once we will drop Ubuntu 18.04 we will use <filesystem> and we should have the compatibility.

Is it ok for you if for now I add if(NOT APPLE) in CMakeLists.txt?

[traversaro]

Is it ok for you if for now I add if(NOT APPLE) in CMakeLists.txt?

Ok, please add a comment mention that this is necessary because of #439 .

[traversaro]

Hi @Nicogene, this PR broke the CI, in particular on Release 2020.08, can you check it? In general when I "Approve" a PR I mean as "We can merge it as long as the CI passes".

[traversaro]

Hi @Nicogene, this PR broke the CI, in particular on Release 2020.08, can you check it? In general when I "Approve" a PR I mean as "We can merge it as long as the CI passes".

Actually I was wrong, the regression in there is not related to that PR, see #441 .