Add RDE Type hooks

[adambarreiro]

Overview

This PR adds a new feature to existing vcd_rde_type resource and data source: The hook blocks.

A hook block maps a lifecycle event of a given Runtime Defined Entity (vcd_rde), one of:

• PostCreate: After the RDE of this type is created
• PostUpdate: After the RDE of this type is updated
• PreDelete: Before the RDE of this type is deleted
• PostDelete: After the RDE of this type is deleted

with an existing Behavior. This allows customers to automatically invoke the desired Behavior when these lifecycle events are triggered.

For example, let's imagine there's a Behavior that calls a webhook to send a message to a Slack channel.
If we have an RDE Type with the new block:

hook {
 event = "PostCreate"
 behavior_id = ... # my "send to Slack" behavior ID
}

Whenever a RDE of that Type is created, it will send a message to Slack!

Implementation details

A new block hook is added to vcd_rde_type resource and data source. This has the sub-properties event (the lifecycle event) and behavior_id.

The Behavior referenced by the ID must exist already.

Tests

Tests passed in VCD 10.5.0

[Didainius]

Thanks. Test also passed in 10.4.0, 10.4.1, 10.4.2