refactor: appconfig and module generators

[liu-hm19]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR refactors the implementations for generating the Spec of AppConfiguration and the call of Kusion Module.

Which issue(s) this PR fixes:

Fixes #1330

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Additional documentation e.g., design docs, usage docs, etc.:

[coveralls]

Pull Request Test Coverage Report for Build 12082624304

Details

• 97 of 132 (73.48%) changed or added relevant lines in 6 files are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.4%) to 49.074%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/generators/secret/secret.go	3	5	60.0%
pkg/generators/util.go	45	54	83.33%
pkg/generators/orderedresources/ordered_resources_generator.go	21	31	67.74%
pkg/generators/namespace/namespace_generator.go	13	27	48.15%

Files with Coverage Reduction	New Missed Lines	%
pkg/engine/operation/parser/parser.go	3	79.27%

Totals
Change from base Build 12065653611:	0.4%
Covered Lines:	10445
Relevant Lines:	21284

---

💛 - Coveralls

[Yangyang96]

LGTM