Remove paper scripts and lines

[barneydobson]

Description

Fixes #140

• Remove everything in the paper module (now at: https://github.com/barneydobson/swmmanywhere_paper) - will add people once I've tested it.
• Remove tests and validation of that stuff
• Enable custom schema (since experimenter will need it for parameters_to_sample).

notes

• Recompiling requirements.txt raised test_derive_subcatchments fails with new pysheds #212
• Once this is closed I will transfer the relevant issues and sort out various PRs

[cheginit]

Except for the comment, the rest looks good.

[dalonsoa]

Looks good to me. I think it makes sense to have the paper-related stuff outside of this repo.