Completed the doc with more charm types

Day-1 and Day-2 are both managed by the VCA (VNF Configuration & Abstraction) module, which consists of a Juju Controller that interacts with VNFs through "charms", a generic set of scripts for deploying and operating software which can be adapted to any use case.

There are two types of charms:

There are three types of charms:

- **Native charms:** the set of scripts run inside the VNF components. This kind of charms are new in Release 7.

- **Proxy charms:** the set of scripts run in LXC containers in an OSM-managed machine (which could be where OSM resides), which use ssh or other methods to get into the VNF instances and configure them.

![OSM Proxy Charms](assets/800px-OSM_nativecharms.png)

- **Proxy charms:** the set of scripts run in LXC containers in an OSM-managed machine (which could be where OSM resides), which use ssh **or other methods** such as HTTP to get into the VNF instances and configure them.

![OSM Proxy Charms](assets/800px-OSM_proxycharms.png)

- **Network Service charms:** This kind of charm is specified at the network service level, and it can invoke actions in the running charms at the VNF level (both native and proxy charms).

![OSM Proxy Charms](assets/800px-OSM_nscharms.png)

These charms can run with three scopes:

- VDU: running a per-vdu charm, with individual actions for each.