refactor: add struct 'KpmClient' to manage the settings of kpm

[zong-zhe]

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):

Add struct 'KpmClient' in pkg/client/client.go to manage the settings of kpm.

Copy the contents of some methods from the pkg/package/package.go and pkg/package/modfile.go into pkg/client/client.go.

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

Before this PR, kpm's methods were controlled through global settings, and the problem was that changing settings would affect all apis.

After this PR, Some methods are moved to pkg/client/client.go as member methods of KpmClient, and these methods are only controlled by KpmClient, and the methods of different KpmClients do not affect each other.

There is no change in the logic of the specific function that has been changed, only some of the original ‘ModFile’ and 'KclPkg' member methods are moved to 'KpmClient'.

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

[Peefy]

Format code.

[Peefy]

LGTM

[coveralls]

Pull Request Test Coverage Report for Build 6296472022

• 364 of 903 (40.31%) changed or added relevant lines in 19 files are covered.
• 70 unchanged lines in 7 files lost coverage.
• Overall coverage decreased (-4.1%) to 38.315%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/settings/settings.go	1	2	50.0%
pkg/cmd/cmd_init.go	0	2	0.0%
pkg/cmd/cmd_login.go	0	2	0.0%
pkg/cmd/cmd_logout.go	0	2	0.0%
pkg/cmd/cmd_pkg.go	0	2	0.0%
pkg/git/git.go	0	2	0.0%
pkg/cmd/cmd_metadata.go	0	3	0.0%
pkg/cmd/cmd_pull.go	0	4	0.0%
pkg/api/kpm_pkg.go	0	5	0.0%
pkg/cmd/cmd_run.go	0	6	0.0%

Files with Coverage Reduction	New Missed Lines	%
pkg/api/kpm_run.go	1	47.47%
pkg/cmd/cmd_pull.go	1	0.0%
pkg/oci/oci.go	1	7.17%
pkg/opt/opt.go	10	9.89%
pkg/package/toml.go	10	71.01%
pkg/package/modfile.go	23	60.31%
pkg/package/package.go	24	48.51%

Totals
Change from base Build 6170701322:	-4.1%
Covered Lines:	1223
Relevant Lines:	3192

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💛 - Coveralls