update tf runtime workspace in stack dir

[markliby]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

2. What is the scope of this PR (e.g. component or file name):

pkg/engine/runtime/terraform/terraform_runtime.go
pkg/engine/runtime/terraform/tfops/

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

The terraform runtime cache directory is in ~/.kusion/.terraform, which cannot support file reading in the stack directory. After the update, the terraform runtime working directory is in the stack directory, and the directory is stackdir/.{ID}

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

6. Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[coveralls]

Pull Request Test Coverage Report for Build 3937715495

• 63 of 101 (62.38%) changed or added relevant lines in 2 files are covered.
• 5 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.04%) to 72.139%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/engine/runtime/terraform/tfops/workspace.go	37	41	90.24%
pkg/engine/runtime/terraform/terraform_runtime.go	26	60	43.33%

Files with Coverage Reduction	New Missed Lines	%
pkg/engine/runtime/terraform/tfops/workspace.go	1	74.21%
pkg/engine/runtime/terraform/terraform_runtime.go	4	46.56%

Totals
Change from base Build 3926938443:	0.04%
Covered Lines:	4596
Relevant Lines:	6371

---

💛 - Coveralls

[SparkYuan]

lgtm