VersionChooser: Allow login for docker daemon by version chooser interface

[JoaoMario109]

Allows users to perform a Docker login to the default Docker registry or custom registries using their Docker username and password or a Personal Access Token (PAT).

Effectively allows for the following:

• Mirrors the functionality of the docker login command.
• Saves credentials to .docker/config.json for both the normal user and the root user (if specified).
• Affects the entire Docker daemon context, enabling all BlueOS services to fetch images or other resources from the authenticated registry.

To access users must be in pirate mode on the version chooser page:

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By default, the dialog logs in using only the normal Raspberry Pi user (not root) and the default Docker registry (https://index.docker.io/v1/).

If needed, users can:

• Authenticate to a custom registry by enabling the Custom Registry switch.
• Use the authentication for sudo docker commands by enabling the Login as Root User switch.

Connected accounts can be seen at the accounts tab. Ones with the shield icon means that the credentials are valid for sudo docker commands.

Validation:

• Trying to pull private repository without login:
  
• Trying to pull private repository after performing login:
  

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NOTE: This PR does not includes the on login authentication check, and does not allows users to test their credentials to check if they still valid. A following PR will add the check, probably matching the auth endpoint docs.

[patrickelectric]

really nice!

[goasChris]

amazing!! This saves my butt when you have a whole swarm of robots on the same outgoing IP ;) thank you very much!