Implement basic Alexa Connector

[dariowho]

AS A framework user
I WANT TO publish my Intents Agent as an Alexa Skill
SO THAT I reach more users without manually porting the Agent

Details

In its simplest form, the connector should include:

• Intents
• Intent parameters (Slots)
• Example Utterances
• Example Utterances with parameter references
• Plain text Responses for later: requires webhook
• System Entities
• Custom Entities (Types)
• Multi-lingual Agents

Input/Output Contexts and Events will not be part of the basic connectors.

Also, Alexa can't be explicitly queried for predictions and triggers: these actions should raise a NotImplementedError

Test Cases

Toy Agent export

GIVEN ToyAgent is defined
AND ToyAgent only imports example_agent.smalltalk.user_name_give
AND AlexaConnector is instantiated with ToyAgent
WHEN ToyAgent is exported and imported into the Alexa Developers Console
THEN A warning is shown, stating that AlexaConnector is experimental
AND The Agent is restored correctly
AND There's a smalltalk.user_name_give intent