Support request bodies components
adds support for request bodies referencing to components/requestBodies/<name> (see spec)
Fixes #595. Sorry I only found #633 after preparing this PR, but in contrast to #633 this one also updates tests (including e2e).
Note – I probably won't have time to continue this for the next few weeks, would be happy if s/o else could pick up :)
@dbanty I think it's complete now, would you mind to take a look?
Disclaimer: I fixed the existing unit tests but did not write new ones especially for the new fetaure. To be honest I didn't really understand what how the tests work and what they actually test. ;-)
Thank you for doing this, and sorry it took so long for me to get around to it. I ended up updating the other PR and finishing off, since there are soo many merge conflicts now (due to my delay).