Community documentation

[ewan-escience]

Community documentation

Changes proposed in this pull request:

• Add documentation on maintaining a community, joining a community and community categories

How to test:

• docker compose down --volumes && docker compose build --parallel && docker compose up --scale data-generation=1
• Check the following sections:
  • http://localhost/documentation/users/community/
  • http://localhost/documentation/users/adding-software/#categories
  • http://localhost/documentation/users/adding-software/#communities

Closes #1186

PR Checklist:

• [ ] Increase version numbers in docker-compose.yml
• [x] Link to a GitHub issue
• [x] Update documentation
• [ ] Tests