doc: Documentation improvements

* Add README.md to the Dockerfiles folder with simple instructions
  to build and run the containers.
* Modify instruction to clone, build and run CAM from a single
  folder in the home, instead of creating multiple folders in the
  home directory.
* Improved getting started page with a new section to setup the
  terminal environment.
* Fix example output of the integration tests.
* Line break for commands that are very long.
* Minor fixes to csc.yml example file and command output.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>