Implemented manifest generation for EB full curation in ingest_envoy

Along the way:

• Added tests for partial-curation manifest generation for ingest_envoy
• Separated IngestionManifestBuilder's directory-to-search (staging_source_dir for ingestion, curation_source for curation) from the directory it wants to put its manifest in since partial curation doesn't always have the former.

apps/cli/executables/pexable/ingest_envoy/ingest_envoy/ingestion_manifest.py

@@ -291,7 +291,7 @@ class IngestionManifestBuilder:
                 )
             self.curation_source = Path(curate[1]) if curate and curate[1] else None
             self.target_list = curate[2]
-            if self.curation_type == CuratorType.FULL and not self.target_list:
+            if self.curation_type == CuratorType.FULL and self.target_list:
                 raise IngestionManifestException(
                     f"Expected targets=None for full curation, got targets={self.target_list}"
                 )