TEZ-4647: Refactor plugin management from DAGAppMaster

[abstractdog]

From Jira:

The proposal is to create a PluginManager to offload much of the plugin management code from the already overloaded DAGAppMaster class (including its static methods).
This issue was discovered while working on TEZ-4007, which only exacerbated the situation with the addition of AMExtensions (not AMExtensions themselves, but rather the original code in DAGAppMaster). Let’s clean this up first before proceeding with TEZ-4007.

Testing done with affected unit tests
mvn install -Dtest=TestTaskSchedulerManager,TestVertexImpl2,TestDAGAppMaster -pl ./tez-dag

[tez-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	25m 31s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	detsecrets	0m 0s		detect-secrets was not available.
+0 🆗	xmllint	0m 0s		xmllint was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 3 new or modified test files.
			_ master Compile Tests _
+1 💚	mvninstall	11m 49s		master passed
+1 💚	compile	0m 46s		master passed
+1 💚	checkstyle	1m 5s		master passed
+1 💚	javadoc	0m 34s		master passed
+0 🆗	spotbugs	2m 33s		tez-dag in master has 785 extant spotbugs warnings.
			_ Patch Compile Tests _
+1 💚	mvninstall	0m 33s		the patch passed
+1 💚	codespell	0m 32s		No new issues.
+1 💚	compile	0m 31s		the patch passed
+1 💚	javac	0m 31s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 17s		tez-dag: The patch generated 0 new + 105 unchanged - 1 fixed = 105 total (was 106)
+1 💚	javadoc	0m 13s		the patch passed
+1 💚	spotbugs	1m 52s		the patch passed
			_ Other Tests _
+1 💚	unit	5m 7s		tez-dag in the patch passed.
+1 💚	asflicense	0m 13s		The patch does not generate ASF License warnings.
		52m 55s

Subsystem	Report/Notes
Docker	ClientAPI=1.51 ServerAPI=1.51 base: https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-428/9/artifact/out/Dockerfile
GITHUB PR	#428
Optional Tests	dupname asflicense codespell detsecrets xmllint javac javadoc unit spotbugs checkstyle compile
uname	Linux 6eaece3b1b08 5.15.0-143-generic #153-Ubuntu SMP Fri Jun 13 19:10:45 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	/home/jenkins/jenkins-home/workspace/tez-multibranch_PR-428/src/.yetus/personality.sh
git revision	master / f0c4020
Default Java	Ubuntu-21.0.8+9-Ubuntu-0ubuntu124.04.1
Test Results	https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-428/9/testReport/
Max. process+thread count	243 (vs. ulimit of 5500)
modules	C: tez-dag U: tez-dag
Console output	https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-428/9/console
versions	git=2.43.0 maven=3.8.7 spotbugs=4.9.3 codespell=2.0.0
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[ayushtkn]

LGTM

[ayushtkn]

can do getLast instead of size -1

[abstractdog]

yeah, absolutely

[tez-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 32s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	detsecrets	0m 1s		detect-secrets was not available.
+0 🆗	xmllint	0m 1s		xmllint was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 3 new or modified test files.
			_ master Compile Tests _
+1 💚	mvninstall	11m 38s		master passed
+1 💚	compile	0m 45s		master passed
+1 💚	checkstyle	1m 5s		master passed
+1 💚	javadoc	0m 34s		master passed
+0 🆗	spotbugs	2m 35s		tez-dag in master has 785 extant spotbugs warnings.
			_ Patch Compile Tests _
+1 💚	mvninstall	0m 32s		the patch passed
+1 💚	codespell	0m 32s		No new issues.
+1 💚	compile	0m 32s		the patch passed
+1 💚	javac	0m 32s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 17s		tez-dag: The patch generated 0 new + 105 unchanged - 1 fixed = 105 total (was 106)
+1 💚	javadoc	0m 12s		the patch passed
+1 💚	spotbugs	1m 51s		the patch passed
			_ Other Tests _
+1 💚	unit	5m 5s		tez-dag in the patch passed.
+1 💚	asflicense	0m 13s		The patch does not generate ASF License warnings.
		27m 46s

Subsystem	Report/Notes
Docker	ClientAPI=1.51 ServerAPI=1.51 base: https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-428/10/artifact/out/Dockerfile
GITHUB PR	#428
Optional Tests	dupname asflicense codespell detsecrets xmllint javac javadoc unit spotbugs checkstyle compile
uname	Linux b36734937aa2 5.15.0-143-generic #153-Ubuntu SMP Fri Jun 13 19:10:45 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	/home/jenkins/jenkins-home/workspace/tez-multibranch_PR-428/src/.yetus/personality.sh
git revision	master / 250a0e2
Default Java	Ubuntu-21.0.8+9-Ubuntu-0ubuntu124.04.1
Test Results	https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-428/10/testReport/
Max. process+thread count	243 (vs. ulimit of 5500)
modules	C: tez-dag U: tez-dag
Console output	https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-428/10/console
versions	git=2.43.0 maven=3.8.7 spotbugs=4.9.3 codespell=2.0.0
Powered by	Apache Yetus 0.15.1 https://yetus.apache.org

This message was automatically generated.

[abstractdog]

thanks @ayushtkn for the review, I'm merging this soon after addressing your comment