Added Documentation Building to Jenkins

[Valenzione]

Hi @KineticCookie, I've added missing dependencies required for building documentation and sketched a groovy function that builds and pushes built documentation to the repo. I'm not sure when I should call it or how to integrate it with a current pipelineCommon. Would you mind giving me a helping hand here?

[KineticCookie]

Hey there!
If your script works fine, you can plug it into different functions depending on when do you want the docs to update:

1. on every push to master - then insert your function call into the https://github.com/Hydrospheredata/hydro-serving-sdk/blob/master/jenkinsfile.groovy#L17
2. on release - insert your function call into the https://github.com/Hydrospheredata/hydro-serving-sdk/blob/master/jenkinsfile.groovy#L3

[Valenzione]

@KineticCookie Thanks, I've added it to the release step. Can you check it? It'd be great to merge this before 2.4.0 stable release

[KineticCookie]

👍