Various fixes & improvements
- Add parallel collect timeout (104) by fpacifici
- move 'what is arroyo for' docs to public docs (103) by volokluev
- Link the official documentation to the readme (102) by fpacifici
- fix(docs) Fix makefile (101) by fpacifici
- Fix branch name in docs generation (100) by fpacifici
- feat(docs) Add a `getting started` page to the docs (99) by fpacifici