Add an explicit v0 version of the protocol

[gosusnp]

What

• To prepare for a more explicit version tracking of the Airbyte Protocol, we should keep track of each major specs of the protocol.

How

Introduce folders with the major version of the protocol.
The new tree would be

airbyte-protocol/protocol-models/src/main/resources/airbyte_protocol/airbyte_protocol.yaml
airbyte-protocol/protocol-models/src/main/resources/airbyte_protocol/v0/airbyte_protocol.yaml
airbyte-protocol/protocol-models/src/main/resources/airbyte_protocol/v1/airbyte_protocol.yaml

For the first iteration, airbyte_protocol/v0/airbyte_protocol.yaml is going to be a symlink towards, airbyte_protocol/airbyte_protocol.yaml.
When we add v1, we should modify airbyte_protocol/airbyte_protocol.yaml to be a symlink towards the most recent version (ie v1).

🚨 User Impact 🚨

There should be no impact since the current file remains the source of truth.

[jdpgrailsdev]

Is the plan to create a ticket/issue right now to track the symlink switch to v1?

[evantahler]

👍 Symlinks are rendered like this in github.

[gosusnp]

Is the plan to create a ticket/issue right now to track the symlink switch to v1?

@jdpgrailsdev, I created #16814 to track this.