First version of new simulation model repository

This is a first pull request for the implementation of the discussed new simulation model repository.

Directory structure:

.
└── simulation-models
    ├── model_parameters
    │   ├── Dummy-Telescope
    │   ├── LSTN-design
    │   │   └── num_gains
    │   └── OBS-North
    │       └── epsg_code  
    └── productions
        ├── 5              # includes all '5'er version (5.0.0, 5.1.0, ...)
        └── 6

Changes to model parameters:

• changed version field to 1.0.0 (from 5.0.0)
• added unique_id field (set to null for now in all cases)
• will add a field schema_version to take into account the possibility that schema might change in future (see also this simtools issues)

simulation-models/productions/5/5.0.0.json is a first version of a production table:

• this will be a very long table (I guess that is fine)
• consciously set {"version": "1.0.0"} to be a dict to allow for easy expansion
• do we need to define a 'design' telescope here? Or do we define all parameters for each telescope explicitly and don't list the design model in the production tables?

Further questions:

• do we want to do name files epsg_code/epsg_code-1.0.0.json or simpler epsg_code/1.0.0.json?