Allow users to delete a project

[gtsiolis]

Problem to solve

Currently, deleting a project is not possible. While eventually the plan is to add projects settings that would allow users to manage and delete a project, a smaller MVC (minimum viable change) could be to introduce a quick way to delete a project using a more actions dropdown on the project card.

Project Cards

[AlexTugarev]

Also important for this to be resolved: a confirmation modal as suggested in https://github.com/gitpod-io/gitpod/pull/4970/files#r678132887

[gtsiolis]

Opened #5034 as a follow-up issue to address the comment in #4704 (comment). Cc @AlexTugarev