refactor: clean runtime unused code, refactor FFI related code & run cargo clippy for the runtime crate

[Peefy]

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

• N
• Y

• refactor: clean runtime unused code, refactor FFI related code & run cargo clippy for the runtime crate

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

• kclvm/runner/src/runner.rs
• kclvm/runtime/src/_kcl_run.rs
• kclvm/runtime/src/api/kclvm.rs
• kclvm/runtime/src/api/utils.rs
• kclvm/runtime/src/base64/mod.rs
• kclvm/runtime/src/file/mod.rs
• kclvm/runtime/src/json/mod.rs
• kclvm/runtime/src/stdlib/builtin.rs
• kclvm/runtime/src/types/constructor.rs

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

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

[zong-zhe]

LGTM

[coveralls]

Pull Request Test Coverage Report for Build 8017660541

Details

• -83 of 113 (26.55%) changed or added relevant lines in 13 files are covered.
• 4 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.01%) to 71.924%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
kclvm/runtime/src/stdlib/builtin.rs	0	1	0.0%
kclvm/runtime/src/api/kclvm.rs	0	2	0.0%
kclvm/runtime/src/base64/mod.rs	0	2	0.0%
kclvm/runtime/src/json/mod.rs	0	2	0.0%
kclvm/runtime/src/yaml/mod.rs	0	2	0.0%
kclvm/runtime/src/file/mod.rs	0	7	0.0%
kclvm/runtime/src/api/utils.rs	0	11	0.0%
kclvm/runtime/src/_kcl_run.rs	0	14	0.0%
kclvm/runtime/src/types/constructor.rs	0	14	0.0%
kclvm/runtime/src/types/kind.rs	0	14	0.0%

Files with Coverage Reduction	New Missed Lines	%
kclvm/runtime/src/api/kclvm.rs	1	43.88%
kclvm/runtime/src/types/str.rs	1	0.0%
kclvm/runtime/src/file/mod.rs	2	0.0%

Totals
Change from base Build 8015464363:	0.01%
Covered Lines:	44241
Relevant Lines:	61511

---

💛 - Coveralls