create_deployment endpoint checks

[albags]

At the moment, it creates a new location_id and a new system_id every time a new deployment is created. However, some checks are missing:

• Check if the location name, lat, and lon exist already, if so, assign the same location_id to the new deployment. (This is when a new AMI is deployed to a location that had another AMI before)
• Check if the camera ID already exists, if so, assign the same system_id to the new deployment. (This happens when an AMI is moved to a new location).