Fix bug 1766: update to latest charm revisions (Charmed installer)

The new revisions include:
 - fixed security issues: secret management
 - Authentication in prometheus and grafana
 - Fix n2vc path in LCM charm (debug-mode)

Change-Id: I4ace5a2e8e7f96883e439047dff739c8a9b40870
Signed-off-by: David Garcia <david.garcia@canonical.com>