Rename DISPaiR struct and crate to Rainlang

[thedavidmeister]

The DISPaiR struct (Deployer/Interpreter/Store/Parser address tuple) in crates/dispair/ represents a complete Rainlang deployment. Under the new branding, this should just be called Rainlang (or similar) since it IS the Rainlang deployment address set.

This would involve:

• Renaming the struct from DISPaiR to something like RainlangAddresses or just using the existing Rainlang concept
• Renaming the crate directory and module accordingly
• Updating all references in the parser and other crates