[FLINK-37412] Add MIN_RESOURCES TaskManagerLoadBalanceMode to maximize TM usage

[vahmed-hamdy]

What is the purpose of the change

• Add RESOURCES allocation strategy to maximize usage of allocated TMs before using another one.

Brief change log

• Added new configuration value RESOURCES for TaskManagerLoadBalanceMode.
• Added mostUtilization allocation strategy to DefaultResourceAllocationStrategy

Verifying this change

• Added relevant UTs

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? NA

[flinkbot]

CI report:

• 2b9d4cb Azure: SUCCESS
• b9b2c93 Azure: PENDING

Bot commands

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• @flinkbot run azure re-run the last Azure build

[XComp]

Thanks for your contribution @vahmed-hamdy . The change looks good. I added a few minor comments. PTAL

[vahmed-hamdy]

@XComp @Poorvankbhatia @RocMarshal thanks all for the review, please have another look if possible

[Poorvankbhatia]

Thanks for taking this up :)

[XComp]

LGTM 👍 One final comment which we could consider.

[XComp]

Suggested change

	resourceCounter ->
	assertThat(resourceCounter.containsResource(largeResource))
	.isTrue());
	}
	resourceCounter -> {
	assertThat(resourceCounter.containsResource(largeResource))
	.isTrue();
	assertThat(resourceCounter.getTotalResourceCount()).isEqualTo(3);
	});

nit: can we also add the expected resource count?