This commit implements the ClusterOverview generation on the Dispatcher. In
order to do this, the Dispatcher requests the ResourceOverview from the
ResourceManager and the job status from all JobMasters. After receiving all
information, it is compiled into the ClusterOverview.

Note: StatusOverview has been renamed to ClusterOverview

This closes #4793.

This closes #4811.

This closes #4791.

This way of passing parameters does not work with the streaming API and
is actually confusing for users.

This closes #4797.

This closes #7807.

This closes #4800.

This closes #4698.

The test did not properly wait for the registration of the TaskExecutor at the
ResourceManager. Therefore, it could come to a race condition between sending
an initial SlotReport and a separate message for the newly added slots.

Previously the QueryableStateClient could connect to the JM
and the TMs directly to fetch the required state. Now, there
is a proxy running on each TM and the remote client connects
to one of these proxies in order to get its state. The proxy
receives the request from the client, performs all necessary
message exchanges within the Flink cluster, receives the state
and forwards it back to the client.

This architecture allows for more security features to be
integrated in the future, as the proxy is running in the
cluster, it exposes less information about the cluster to
the outside world, and is more suitable for containerized
environments.

Creates a separate for the queryable state and  moves the client
code outside the runtime. The Task Manager is now instantiating
the KvStateServer using reflection.

This closes #4772.

This closes #4789.

This closes #4792.

This closes #4624.

This closes #4585.

This closes #4785.

This closes #4625.

This closes #4768.

Disable failing when not all creator properties are known

Move CheckpointStatsCache out of legacy package; Remove unused CheckpointingStatistics#generateCheckpointStatistics method

Remove JsonInclude.Include.NON_NULL from CheckpointStatistics; Pull null check out of CheckpointStatistics#generateCheckpointStatistics; Make CheckpointStatistics#checkpointStatisticcsPerTask non nullable; Add fail on missing creator property

This closes #4763.

This close s#4788.

This closes #4735.

This closes #4499.

This closes #4485.

Before, we were printing the exception (and stack trace) when the Async
I/O Emitter was receving an interrupted exception. The interrupt,
however is part of the normal shutdown process of the Emitter and the
log message was causing concern because a stack trace usually indicates
something went wrong.

Refactor the current usage of on Cassandra Sink w/ more in-depth information.

Provides examples for Pojo and Java Tuple data types

This closes #4696.

This closes #4760.

This closes #4756.

[FLINK-7072] [REST] Extend Dispatcher

[FLINK-7072] [REST] Add handlers for job submit/cancel/stop

[FLINK-7072] [REST] CLI integration

use ExecutorThradFactory + rebase(blobKey fix)

add "Flink" prefix to RestCC threads

shutdown client for cancel/shutdown

Rework CliFrontEnd Stop/Cancel tests

These tests verified that the CLI was sending the correct messages and
parameters to the JM actor. This is now handled by the ClusterClient, so
the tests were adjusted to verify that the correct methods on the
ClusterClient are being called.

Additional tests were added to the ClusterClientTest class to verify
that the correct messages and parameters are being sent.

This closes #4742.