Add tutorial files to testsuite

Description

Added all the input files from the Octopus basics tutorial to the testsuite. This way we can make sure we don't break the tutorial. Also, all the required changes to the input files and to key results due to changes in the code are tracked within git, so we can use that information to update the tutorials when there is a new major release.

News snippet

Added all the input files from the Octopus basics tutorial to the testsuite.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.