WfExS-backend init issues

[jmfernandez]

WfExS-backend init should create valid yaml configuration files when --cache-dir parameter is provided. Also, it should validate already existing configuration files against the corresponding JSON schema.

An example of the bad behaviour:

(.pyWEenv) jmfernandez@pavonis[14]:~/projects/WfExS-backend> python WfExS-backend.py --cache-dir /tmp/gorrito -L prueba2.yaml init
[WARNING] Configuration file prueba2.yaml does not exist
[WARNING] Cache directory not defined. Created a temporary one at /tmp/wfexsrkoltayctmpcache
2024-01-31 10:54:02,182 - [WARNING] [WARNING] Installation key file /home/jmfernandez/projects/WfExS-backend/prueba2.yaml.key does not exist
2024-01-31 10:54:02,182 - [WARNING] [WARNING] Installation pub file /home/jmfernandez/projects/WfExS-backend/prueba2.yaml.pub does not exist
* Storing updated configuration at prueba2.yaml
(.pyWEenv) jmfernandez@pavonis[15]:~/projects/WfExS-backend> cat prueba2.yaml
cache-directory: /tmp/gorrito
cacheDir: /tmp/wfexsrkoltayctmpcache
crypt4gh:
  key: prueba2.yaml.key
  passphrase: ndcart ndredth ndline elling
  pub: prueba2.yaml.pub