Adding new global variable for NSSMF adapter from SO module in robot_properties.py file.

This variable will be used as a part of healthcheck under SO unit.

Proposal :

Health Check improvement proposal
API handler validation : Already in existence
By sending any GET request and validating response
Data Stores validation : Already in existence
1. Request DB : Validation of request db by fetching any data instance if present else putting dummy data and validating afterwards
2. Catalog DB : Validation of request db by fetching any data instance if present else putting dummy data and validating afterwards
Adapter validation : Implementing for NSSMF. Already existing for VNF and VNFM
By providing get request and validate the response (for Bell utilized adapters nssmf, ve-vnfm, vfc and vnfm)
Execution engine validation :
 Since execution engine does not contact with external API hence it tough to find any light weight API which can describe healthiness of this sub-module. Still we are trying to find any API which can full-fill our health check → consider instead to handle as part of api handler testing?

Updates
Reviews from Sebastien Premont-Tendland : (9/4/202)
Suggestion : Include nssmf, ve-vnfm, vfc, vnfm adapter validation
Implementation: nssmf adapter is added
vfc, vnfm adapters area already present