Verify all conditions of core eventing resources and make sure they are actionable and useful

[capri-xiyue]

Describe the bug
The conditions of some eventing resources are confusing. For example,
the subscribed of Trigger is used when we subscribe to broker channel. However, in Trigger, we have subscriber. User might feel subscribed is to indicate the status of subscriber. We should go through the conditions of core eventing resources and make sure they are actionable and useful.

Expected behavior
The conditions of core eventing resources is clear, actionable and useful.

[capri-xiyue]

This is related to #1740

[capri-xiyue]

I checked the core eventing resources and list the conditions that I think should get renamed as follows:

Resource	Condition Origin Name	Condition Updated Name
subscription	Resolved	ReferenceResolved
trigger	Broker	BrokerReady
trigger	Subcribered	SubscriptionReady
trigger	Dependency	DependencyReady

[capri-xiyue]

/assign

[grantr]

/label proposal/0.13

[grantr]

/remove-label proposal/0.13
/label proposal/0.14

[grantr]

Remaining renames from the list above:

Resource	Condition Origin Name	Condition Updated Name
subscription	Resolved	ReferenceResolved
trigger	Subcribered	SubscriptionReady