Support builds without exceptions

[oleid]

To be able to use zenoh-cpp in an exception free environment such as micro-controllers, the following minimally-invasive change provides a THROW_ZEXCEPTION macro, which compiles down to simply calling abort() if exceptions are disabled.

Since exceptions are the standard case, I think it doesn't make sense to change all the doxygen comments. I updated the documentation on error handling, though.

[oleid]

It would appear that the windows build is a bit unreliable. I don't see a way to trigger only the failed build. Maybe a maintainer can help.

[DenisBiryukov91]

@oleid I'm wondering if it would be more appropriate to make zenoh::ZResult argument in every function mandatory in case exceptions are not supported, to prevent unexpected abort() calls.

[oleid]

@oleid I'm wondering if it would be more appropriate to make zenoh::ZResult argument in every function mandatory in case exceptions are not supported, to prevent unexpected abort() calls.

Sure, that would result in fewer surprises, however, would increase the diff considerably.
But if you prefer that solution, I'm happy to change the commit.

[oleid]

@DenisBiryukov91 Just checked. Trouble is: in most cases, there are optional arguments in front of the ZResult out-ptr. Therefore, the pointer must have a default value. And I can't change the order of arguments without breaking the API.