Allow naming entities as: Schema, Belt, EntityHistory, InternalEntity, Entity, Utils

[DZakh]

• Vendor @ryyppy/rescript-promise to reduce installation and compile time
• Move more files into the npm package from codegen.
• Improve dependency graph to depend less on the generated files and improve modularity and testing
• Deleted unused code from DbFunctions
• Moved global Db state into the single Db.res module. DbFunctions.res doesn’t contain any global state anymore
• Restructured the Entites.res modules, so now ReScript doesn’t complain on entities with the following names: Schema, Belt, EntityHistory, InternalEntity, Entity, Utils. Previously there were name collisions which wouldn’t allow to name entities in schema.graphql like this.

[JasoonS]

Awesome - it looks good on reading through. Didn't analyse super deeply - but in the type system I trust 💪