feat: support spec file as input of preview and apply

[liu-hm19]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR supports the --spec-file flag in kusion preview and kusion apply.

Which issue(s) this PR fixes:

Fixes #

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 9659798441

Details

• 11 of 60 (18.33%) changed or added relevant lines in 2 files are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.1%) to 54.103%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/cmd/apply/apply.go	5	29	17.24%
pkg/cmd/preview/preview.go	6	31	19.35%

Files with Coverage Reduction	New Missed Lines	%
pkg/cmd/apply/apply.go	1	50.3%
pkg/cmd/preview/preview.go	2	39.57%

Totals
Change from base Build 9658530204:	-0.1%
Covered Lines:	9124
Relevant Lines:	16864

---

💛 - Coveralls

[SparkYuan]

lgtm