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/prometheus/config.yaml b/installers/charm/prometheus/config.yaml
index baa04cd..d953de3 100644
--- a/installers/charm/prometheus/config.yaml
+++ b/installers/charm/prometheus/config.yaml
@@ -20,11 +20,11 @@
 ##
 
 options:
-  web_subpath:
+  web-subpath:
     description: Subpath for accessing Prometheus
     type: string
     default: /
-  default_target:
+  default-target:
     description: Default target to be added in Prometheus
     type: string
     default: ""