Make max_connections and innodb_buffer_pool_size configurable
through soft params instead of hard.

Change-Id: Id0bb8f6b6091289275864bf4dd6a6890d11b4782

Change-Id: Ia6873c44f4e5b179a6c4a545fbf4b45c978812ea

Change-Id: Iec2d27cc4fdab9ba7772e9c26be66ba54f5aadfc
Depends-On: Ice4f38abfb0d870c56763dfeda2140032fa752a1

This patch enables support for Grafana and provides a new dashboard.

This also installs 2 additional packages (libdbd-mysql and
python-pymysql) that are required for running the collectd plugins.