Update SemanticManifestTransformer to expect a generic bound by the SemanticManifest Protocol

[QMalcolm]

Currently the SemanticManifestTransformer (currently named ModelTransformer) expects and returns a UserConfiguredModel which is a concrete object. Initially we thought we should move to it expecting and returning a SemanticManifest protocol. However, in dbt-core we'll be writing nodes which extend the protocol definition. Additionally we want to be able to hand in raw-ish parsings and transform them into the final objects, meaning the input and return types should be different. If we want to be able to write transformation rules that can operate on the raw parsed objects, return the extended classes, and guarantee type safety, then we need to take it a step further. Thus the SemanticManifestTransformer should instead expect a generic and return a generic bound by the SemanticManifest protocol.

Something like...

from typing import TypeVar
from dbt_semantic_interfaces.protocols import SemanticManifest


T = TypeVar("T", bound="SemanticManifest")
U = TypeVar("U")

class SemanticManifestTransformer:
  ...

  @staticmethod
  def transform(
    raw_semantic_manifest: U,
    ordered_rule_sequences: Tuple[Sequence[SemanticManifestTransformRule], ...] = DEFAULT_RULES,
  ) -> T:
    ....