Feat: add cue strategyUnify provider

[yangsoon]

Thie PR add strategyUnify provider for user to strategy patch the cue Value, The signatures of the strategyUnify provider are as follows:

#StrategyUnify: {
	#do:       "strategyUnify"
	#provider: "cue"

	// +usage=The params of this action
	$params: {
		value: {...}
		patch: {...}
	}

	// +usage=The result of this action
	$returns: {...}
}

The $params.value represents the original object to be patched，$params.patch describe patch action, The behavior of $params.patch is consistent with that of patch in TraitDefinition, So you can describes patch behavior strategically with tags patchKey or patchStrategy.

A simple example is as follows:

import "vela/cue"
patch: cue.#StrategyUnify & {
	$params: {
		value: {
			containers: [{
				name: "x1"
			}, {
				name:  "x2"
				image: "redis:latest"
			}]
		}
		patch: {
			// +patchKey=name
			containers: [{
				name: "x2"
				// +patchStrategy=retainKeys
				image: "nginx:latest"
			}]
		}
	}
}

==> after  compiler

patch: cue.#StrategyUnify & {
	$params: {
         ...
	}
	$returns: {
		// +patchKey=name
		containers: [{
			name: "x1"
		}, {
			name: "x2"
			// +patchStrategy=retainKeys
			image: "nginx:latest"
		}]
	}
}

[codecov]

Codecov Report

Patch coverage: 71.61% and project coverage change: -3.96 ⚠️

Comparison is base (d7022ea) 90.27% compared to head (b6c45af) 86.31%.

❗ Current head b6c45af differs from pull request most recent head 5cc41bd. Consider uploading reports for the commit 5cc41bd to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #70      +/-   ##
==========================================
- Coverage   90.27%   86.31%   -3.96%     
==========================================
  Files          68       72       +4     
  Lines        2529     3209     +680     
==========================================
+ Hits         2283     2770     +487     
- Misses        179      333     +154     
- Partials       67      106      +39     

Flag	Coverage Δ
unit-test	86.31% <71.61%> (-3.96%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
cue/cuex/model/sets/walk.go	62.63% <62.63%> (ø)
cue/cuex/providers/cue/cue.go	66.66% <66.66%> (ø)
cue/cuex/model/sets/operation.go	72.72% <72.72%> (ø)
cue/cuex/model/sets/utils.go	73.35% <73.35%> (ø)
cue/cuex/compiler.go	83.19% <100.00%> (+0.14%)	⬆️

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[FogDong]

It would be nice if we can add more tests to cover the code, generally LGTM, great job!