[Feature] Support alter table merge partitions

[meegoo]

Why I'm doing:

What I'm doing:

Fixes #56843

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
  • I have added documentation for my new feature or new function
• This is a backport pr

Bugfix cherry-pick branch check:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 3.4
  • 3.3
  • 3.2
  • 3.1
  • 3.0

[sonarqubecloud]

Quality Gate failed

Failed conditions
35.2% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud

[github-actions]

[Java-Extensions Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[BE Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[FE Incremental Coverage Report]

❌ fail : 377 / 507 (74.36%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
🔵	com/starrocks/sql/analyzer/AlterTableClauseAnalyzer.java	16	22	72.73%	[434, 441, 445, 449, 454, 455]
🔵	com/starrocks/alter/MergePartitionJob.java	343	464	73.92%	[145, 149, 155, 183, 184, 185, 193, 219, 220, 221, 226, 227, 248, 252, 256, 264, 275, 276, 277, 306, 311, 312, 314, 315, 326, 330, 337, 346, 402, 403, 404, 430, 435, 455, 456, 469, 470, 475, 476, 482, 483, 516, 532, 543, 544, 545, 546, 547, 548, 549, 550, 551, 553, 559, 600, 609, 611, 620, 621, 622, 632, 633, 635, 637, 638, 639, 640, 641, 642, 643, 644, 649, 650, 652, 653, 654, 657, 658, 661, 662, 663, 664, 667, 668, 669, 671, 672, 673, 674, 675, 676, 678, 679, 680, 681, 683, 684, 685, 687, 689, 693, 694, 695, 696, 698, 700, 716, 721, 744, 749, 815, 816, 817, 818, 819, 820, 836, 837, 861, 862, 877]
🔵	com/starrocks/sql/analyzer/AnalyzerUtils.java	10	13	76.92%	[1384, 1398, 1586]
🔵	com/starrocks/alter/OptimizeJobV2Builder.java	6	6	100.00%	[]
🔵	com/starrocks/alter/AlterJobV2.java	1	1	100.00%	[]
🔵	com/starrocks/persist/gson/GsonUtils.java	1	1	100.00%	[]