Implement version + release schedule

(Note: general eegnb dev discussions to be relocated to github DIscussions on this page.

We are going to merge the develop branch to master, which contains two main new components: the refactored experiment class and the analysis report function.

As part of doing this, we will implement a more structured release schedule process, which will allow us to more easily keep on top of changes and comfortably execute releases / merge updates to master that might possibly cause backwards compatibility issues.

Overall tasks:

• Confirm we are ready to move develop branch contents into master (Taha)
  • Check the code runs (again) (Taha)
  • Check for any API changes from previous version, and either adjust if possible or document (Taha)
  • Write docs on new features (analysis report; maybe others) (Taha)
  • Update docs on anything major that's missing (Taha)
  • Check docs in general; esp. installation (Taha; John)
• Write doc describing this version plan ( John )
• Create new branch from current master, called 0.2 (current version) (John)
• Create new branch from develop, called 0.3 (new version) (John)
  • Check requirements are up to date
  • Make changelog file
  • Remove Parv submodule [Ore]
• Merge 0.3 to master (John0)
• Add pypi installation for 0.3 onwards (Ore)
• Add multi-version doc build configuration (c.f. github.com/mne-tools.github.io) (Taha)