Resolve "Component: Add Forms documentation"
I wrote down the form guidelines based on the discussion from gitlab-org/gitlab-design#154 (closed)
I deleted the Datepicker and Validations pages because I added them to form guidelines. Will correctly link to the Sketch specs for forms, once those are merged.
@sarrahvesselov can you review when you have time, please? No rush
Edited by Matej Latin