Multiple static registries

[Joxit]

Add support for default registries (options DEFAULT_REGISTRIES) you can add many registries separated with a comma.

Example:
DEFAULT_REGISTRIES=https://registry.example.com,https://registry2.example.com,http://localhost:5000

Add also read only registries (option READ_ONLY_REGISTRIES) that deactivate add and remove for registries.

These options works only when SINGLE_REGISTRY=false

Behaviors:

• DEFAULT_REGISTRIES:
  • will set the list of registries in the localstorage when the localstorage is empty.
  • will overwrite the list of registries every time when READ_ONLY_REGISTRIES=true
• READ_ONLY_REGISTRIES:
  • will remove dialog for Add and Remove registries

resolves #211