Merge branch 'change_naming_charms' into 'master'

- VNF: running globally for the VNF, for the management VDU that represents it.

- NS: running for the whole NS, after VNFs have been configured, to handle interactions between them.

Depending on the scope of charms, the charm application naming differs:

- **The VNF level** charm application name is prepared by combining the relevant execution environment name and vnf-profile-id.

- **The VDU level** charm application name includes vdu-profile-id as an identifier together with the relevant execution environment name and vnf-profile-id that it belongs.

- **The NS level** charm application name is identified with the charm name. 

The structure of charm application name makes the charm more apparent. Besides, it makes the VDU/KDU more visible by looking through the related charm. The structure of charm application names which are limited with 50 characters, are described below according to scope of charms:

```bash

NS level: <charm-name>-ns

VNF level: <ee-name>-z<vnf-ordinal-scale-number>-<vnf-profile-id>-vnf

VDU level: <ee-name>-z<vnf-ordinal-scale-number>-<vnf-profile-id>-<vdu-profile-id>-z<vdu-ordinal-scale-number>-vdu

```

For detailed instructions on how to add cloud-init or charms to your VNF, visit the following references:

- [VNF Onboarding Guidelines, Day-0](https://osm.etsi.org/docs/vnf-onboarding-guidelines/02-day0.html)