Rename the repository to complete the Theia Blueprint to Theia IDE rebranding

[dannaf]

As mentioned here, eclipse-theia/theia-website#524 (comment), this will not occur by itself. At some point someone will have to do it, so it should be tracked with an open issue.

[dannaf]

I suggest Eclipse/admins rename this repository from theia-blueprint to theia-ide, then, if you want to still support users who may still reach the https://github.com/eclipse-theia/theia-blueprint url for whatever reason, create a new repository calld theia-blueprint (after renaming this repository) and create a simple README that directs the user to https://github.com/eclipse-theia/theia-ide instead, and archive that repository.

[dannaf]

Another task for resolving this issue is to remove the section of the Theia IDE README titled Theia IDE vs Theia Blueprint.

[dannaf]

One place where theia-blueprint still appears currently is in the Theia Cloud online demo from theia-ide.org