Add enum constants to init for direct import (#1184)

A very minor change aimed at improving the developer experience. As
mentioned
[here](#1107 (comment)),
certain constants from `cosmos.constants`, such as `ExecutionMode`,
`LoadMode`, or `TestBehavior`, are already imported in the `__init__`
file to facilitate direct imports.

However, other constants are not currently included, which leads to an
inconsistent import pattern when setting dbt configurations.

This PR adds the remaining enumerations: `InvocationMode`,
`TestIndirectSelection`, `SourceRenderingBehaviour`, `DbtResourceType`.

Closes #1183

cosmos/__init__.py

@@ -16,7 +16,15 @@
     ProjectConfig,
     RenderConfig,
 )
-from cosmos.constants import ExecutionMode, LoadMode, TestBehavior
+from cosmos.constants import (
+    DbtResourceType,
+    ExecutionMode,
+    InvocationMode,
+    LoadMode,
+    SourceRenderingBehavior,
+    TestBehavior,
+    TestIndirectSelection,
+)
 from cosmos.log import get_logger
 from cosmos.operators.lazy_load import MissingPackage
 from cosmos.operators.local import (
@@ -157,6 +165,10 @@
     "ExecutionMode",
     "LoadMode",
     "TestBehavior",
+    "InvocationMode",
+    "TestIndirectSelection",
+    "SourceRenderingBehavior",
+    "DbtResourceType",
 ]
 
 """