fix: align terraform resources with actual provider schema

Use nested attribute assignment instead of dynamic blocks for
specifications, quality_groups, and format_items. Remove unsupported
season_search_maximum_single_episode_age from indexer configs. Flatten
custom format specifications to use value/min/max directly.

config/custom_format/source_webdl.yaml

@@ -1,16 +1,12 @@
 include_custom_format_when_renaming: false
 specifications:
-  - name: webdl
-    implementation: SourceSpecification
-    negate: false
-    required: false
-    fields:
-      - name: value
-        value: "3"
-  - name: webrip
-    implementation: SourceSpecification
-    negate: false
-    required: false
-    fields:
-      - name: value
-        value: "4"
+- name: webdl
+  implementation: SourceSpecification
+  negate: false
+  required: false
+  value: '3'
+- name: webrip
+  implementation: SourceSpecification
+  negate: false
+  required: false
+  value: '4'