Make v7 the default version

[OverHash]

Rojo v7.0 has been released and is fairly stable. It is therefore fair to make it the default version used when exploring the Rojo docs.

These changes were achieved in the following steps:

• Modify versions.json to change from v7 to v6
• Move all files in docs/ into a new folder, versioned_docs/version-v6
• Move all files from versioned_docs/version-v6 into docs (and delete the folder)
• Rename versioned_sidebars/version-v7-sidebars.json to become v6 (and the file contents)
• Update src/pages/index.js to make the splash screen direct to the v7 version of the docs
• Update the versions field in docusaurus.config.js

[LPGhatguy]

Many of these pages are intentionally shared between the versions, so some care has to be taken to not introduce duplicates of them. You can see that in a lot of the pages that import other pages and reexport their bits.

I'll take some time to review this, but testing is a little tricky because of how finnicky Docusaurus can be.

[OverHash]

Many of these pages are intentionally shared between the versions, so some care has to be taken to not introduce duplicates of them. You can see that in a lot of the pages that import other pages and reexport their bits.

Agreed. In the future, I think it should be considered to copy the state of docs/ into the versioned docs so that the documentation is not spread out or dependent on anything, but in more of an archival state.

I did as much testing as I could locally with Docusaurus and could not find any issues with these changes, but I understand that there can be time required to test out the changes.

[OverHash]

Just cherry-picked the commit from #65 into this PR. Once that PR has been resolved, the diff should be cleaner.

[LPGhatguy]

Thanks for submitting this PR!

I ended up doing the same work locally, which was easier to review as I went.