rework to separate out python module

Remove the magic from the magic _db* modules.
Combine as one 'devsup._dbapi'.

libpyDevSup exists only to bootstrap python
interpreter in IOCs.

devsupApp/src/devsup/hooks.py

@@ -4,10 +4,7 @@ import traceback
 from functools import wraps
 from collections import defaultdict
 
-try:
-    import _dbapi
-except ImportError:
-    import devsup._nullapi as _dbapi
+from . import _dbapi
 
 __all__ = [
     "hooknames",