Update package names back to @nomicfoundation

[kanej]

The final change to the code will be to update both:

• the package names to their original package names
• the version to indicate a v3.0.0 pre-release

This will require using changeset's prerelease mechanism.

Along with a PR that can be merged as part of the final release process, we will also need a short doc that walks through each step of the release.

TODO

• Update the package names to be under @nomicfoundation
• Update the versions inline with a 3.0.0 pre-release
• Update the changeset config
• Write and attach the document listing the steps required to release the packages on npm with prerelease versions
• Manually test the release locally against Verdaccio confirming the release guide

[alcuadrado]

This may require some updates to the typechain plugin, as we had to do some hacks around package names. /cc @ChristopherDedominici