Docs: Add note with summary for adding a VCS integrated project

This should act as a clear and concise summary that explains in 3 steps
how to add a new project integrated with a VCS.
Docs: Add new section to encompass the docs for working with VCS projects

This should avoid confusion in readers by putting apart the VCS project
setup docs and the docs for working with already configured VCS projects.
Docs: minor fix to keep length below 80 chars
Docs: Use PODIRECTORY instead po in example paths in directory layouts table
Docs: minor change
Docs: Use tree-like directory layout example