feat: add more error checks in the normalizer

[mhmd-azeez]

• make sure all required properties are actually defined
• make circular references illegal (this blows up JSON.stringify even in NodeJS)
• the normalizer returns multiple errors now
• fix: when a property is untyped (object with no properties), the xtpType.name is set to the property name.
  

  xtp-bindgen/tests/index.test.ts

  Line 68 in 2ec57e5

  expect((properties[8].xtpType as ObjectType).name).toBe("")

  
  

  xtp-bindgen/tests/schemas/v1-valid-doc.yaml

  Lines 108 to 110 in 2ec57e5

  	anUntypedObject:
  	description: An untyped object with no properties
  	type: object

• check for invalid identifiers: exports/imports/schemas/properties/enums
• add more tests

[bhelx]

Something about this function feels too big. I wrote some code to workaround cycles by storing cycles then processing them later. so part of that was detecting cycles and storing them. and it was only a few lines of code. Perhaps i was missing something though. Either way i think this is good because it's separate from the main parse and normalize code so we can easily remove it later.