Add pytest setup for each package

This MR adds consistent pytest configurations across the gstlal packages.

Changes:

• add pytest directory and config file for each package
• add build suite for each package (if not already present)

gstlal/python/utilities/Makefile.am

@@ -3,4 +3,5 @@ utilitiesdir = $(pkgpythondir)/utilities
 
 utilities_PYTHON = \
 	__init__.py \
-	admin.py
+	admin.py \
+	testtools.py