Adopt changes in Core 2.0

[prudrabhat]

Description

In this PR :

 - .gradle changes
    - Add jitpack to repositories
    - Consume Core 2.0 via com.github.adobe.aepsdk-core-android:core:de-v2.0.0-SNAPSHOT
      from jitpack
    - Prevent transitive dependencies from other extensions
    - Change moduleVersion, mavenCoreVersion to 2.0.0.

 - Change IdentityConstants.EXTENSION_VERSION to 2.0.0
 - Expose IdentityExtension.class via Idenity.EXTENSION
 - Switch to MobileCore.dispatchEventWithResponseCallback(event, timeout, callbackWithError)
   and ExtensionApi.dispatch(event)

 - Switch to using new shared state api
   - Remove multiple instance creation of SharedStateCallback.
   - Streamline shared state calls via SharedStateCallback within and
      outside the Identity extension

 - Implement IdentityExtension.onRegistered()
   - Change event listener registration to be done in onRegistered() instead of the
     IdentityExtension's constructor
 - Remove Listener*.java classes in favor of inline methods
   - Remove the inhouse executor service and mutex as the events are now incident
     via a single thread maintained by the extension container housing this extension.

 - Implement IdentityExtension.readyForEvent()
   - Add logic to wait for EventHub state and IdentityDirect registration check
     if ECID from persisted properties is unavailable.
   - Remove the logic to cache events internally. Take advantage of the Hub
     shared state fetching to boot up and disambiguate between Identity direct and
     EdgeIdentity.

 - Switch to use public utility classes and methods from Core where applicable
   - Use StringUtils.isEmpty()
   - Use JSONUtil.toMap() and JSONUtil.toList()
   - Use TimeUtils
   - Use DataReader.opt*() to read and parse event data. Remove class cast
     exception guards and resolve unchecked cast warnings where possible.

 - General changes done on code path toched
   - private and finals where applicable
   - Use cascading constructors to eliminate constructor divergence risk and
     ease test injection

Out of scope for this PR

 - Switching to Log from MobileCore.Log
 - Using EventSource and EventType from Core
 - Switching to ServiceProvider
 - Switching IdentityStorageService to NamedCollection
 - Test changes
 - PowerMock elimination

Related Issue

MOB-17065

Motivation and Context

Core 2.0 changes will allow architectural consistency with iOS.

How Has This Been Tested?

• Verified that the ci-build passes locally.
• Verified operations from test app
• Unit tests and integration tests (not in this PR) in progress.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[emdobrin]

do we need to add similar logic in iOS to ensure hub ss is ready before bootup?
cc @kevinlind

[kevinlind]

I think it would be safe to add this to iOS as well. I don't remember the full conversation but I was under the impression that the EventHub shared state was the first (or one of the first) events dispatched when the SDK starts. Adding a check like this for the EventHub shared state makes the code more robust, so it's a good idea.

[kevinlind]

The documented API timeout is 500 ms. The timeout is short primarily because of getExperienceCloudId, which needs to be fast for customers implementing a hybrid application which contains a web view. As these APIs are time sensitive for customers, I'd suggest keeping the 500 ms value.
cc @emdobrin

[prudrabhat]

I did not realize that the documented value of timeout is 500ms and so made it match the default max timeout for a response callback instead.
I have now changed it to 500ms to match the documented contract 👍🏼