feat: more api and examples

[Peefy]

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

• N
• Y

• feat: more api and examples

[coveralls]

Pull Request Test Coverage Report for Build 9974711504

Details

• 45 of 456 (9.87%) changed or added relevant lines in 15 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.1%) to 32.797%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/native/client.go	0	3	0.0%
pkg/service/grpc_server.go	0	3	0.0%
pkg/loader/options.go	0	4	0.0%
pkg/loader/package.go	0	4	0.0%
pkg/loader/variables.go	0	4	0.0%
pkg/parser/parser.go	0	4	0.0%
pkg/tools/module/module.go	0	4	0.0%
pkg/service/rest_server.go	2	7	28.57%
pkg/service/client_kclvm_service.go	0	6	0.0%
pkg/kcl/version.go	0	7	0.0%

Files with Coverage Reduction	New Missed Lines	%
pkg/spec/gpyrpc/gpyrpc.pb.go	2	3.88%

Totals
Change from base Build 9917678853:	-0.1%
Covered Lines:	5685
Relevant Lines:	17334

---

💛 - Coveralls