Major improvement in OSM charms

- Adapt all new operator charms to use the same pattern. They are all
using now this library that encapsulates the common logic for all
charms: https://github.com/davigar15/ops-lib-charmed-osm. That will be
eventually moved to gitlab, when it has a PyPI repository available
- Add unit tests to all charms
- Modify installer and bundles to point to the new charms
- Improve the build.sh script for building the charms

Change-Id: I0896ceb082d1b6a76b3560c07482a4135a220a3f
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/installers/charm/generate_bundle.py b/installers/charm/generate_bundle.py
index 95ffeaa..a82e016 100644
--- a/installers/charm/generate_bundle.py
+++ b/installers/charm/generate_bundle.py
@@ -49,7 +49,7 @@
 path = HA_BUNDLE if args.ha else DEFAULT_BUNDLE
 destination = args.destination
 prefix = "." if args.local else BUNDLE_PREFIX
-suffix = "/release" if args.local else ""
+suffix = "/build" if args.local else ""
 
 data = {
     "channel": channel,