feat: helper function in ioutil to PrintObjectAsTree

[Horiodino]

PR Summary

Fixes Issue: #545

Description of Changes:

• Added a new helper function, PrintObjectAsTree, in the ioutil package to improve functionality.
• Refactored the code by removing the redundant tree package from the internal package, as it is no longer needed.

[JeyJeyGao]

@Horiodino Thanks for your contribution! Please fix the license and E2E test and add unit tests to cover the new code.

[FeynmanZhou]

@Horiodino You can check the CI running results to figure out the failure reasons. In general, you will need to add license header and E2E test to your code changes.

[Horiodino]

No problem, almost done. I'll let you know once I push it. 👍

[Horiodino]

I've identified and resolved an issue with the test cases. Initially, there wasn't a problem with the test cases themselves, but I had missed adding the |_ for some, which caused some tests to fail. I've fixed this, and now all test cases should pass.

However, there is one test case that might still be failing: notation/test/e2e/suite/command/sign.go:297. I have cross-checked with the main repository and don't believe this failure is due to my recent commits, but please verify.

[Horiodino]

all passed expect the one i mentioned above

Summarizing 1 Failure:
  [PANICKED!] notation sign [It] with timestamping and invalid tsa server
  /home/holiodin/notation/test/e2e/internal/utils/matcher.go:91

Ran 90 of 100 Specs in 30.494 seconds
FAIL! -- 89 Passed | 1 Failed | 0 Pending | 10 Skipped


Ginkgo ran 4 suites in 31.385041704s

There were failures detected in the following suites:
  command ./suite/command

Test Suite Failed
Cleaning up...
Zot stopped
notation-e2e
Stopping CRL server...
make: *** [Makefile:62: e2e] Error 1```

[codecov]

Codecov Report

Attention: Patch coverage is 64.61538% with 46 lines in your changes missing coverage. Please review.

Project coverage is 70.25%. Comparing base (2ff8754) to head (3bbefe6).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/ioutil/tree.go	65.51%	34 Missing and 6 partials ⚠️
cmd/notation/inspect.go	57.14%	2 Missing and 1 partial ⚠️
cmd/notation/list.go	57.14%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1129      +/-   ##
==========================================
- Coverage   70.79%   70.25%   -0.55%     
==========================================
  Files          48       48              
  Lines        2945     3026      +81     
==========================================
+ Hits         2085     2126      +41     
- Misses        668      701      +33     
- Partials      192      199       +7     

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[JeyJeyGao]

@Horiodino Sounds good! You have fixed the license and E2E. However, the test coverage doesn't reach 80%. You may need to add unit tests to improve the coverage. Thanks!

[JeyJeyGao]

@Horiodino Could you sign your commit by follow the guide.

[Horiodino]

@Horiodino Could you sign your commit by follow the guide.

I already signed the commit

[JeyJeyGao]

It looks like this PR doesn't need to update the go.mod.

[JeyJeyGao]

@Horiodino Could you sign your commit by follow the guide.

I already signed the commit

You may need GPG key signing for the commit. Please have a look at the guide.