feat: add coverage command

[k1LoW]

This pull request introduces a new pipeline resolver step coverage feature and improves the user experience of several commands by adding a spinner to indicate progress. It also enhances the flexibility of resource loading with new options and adds support for fetching resolver execution results for coverage calculation. Several new dependencies are introduced to support these features.

New Coverage Feature:

• Adds a new coverage command (cmd/coverage.go) that displays pipeline resolver step coverage, including options for time filtering and detailed reporting. This command uses a new Coverage method on the Client to analyze step coverage based on recent execution results. [1] [2]

User Experience Improvements:

• Adds a spinner (progress indicator) to the lint and metrics commands to provide visual feedback during long-running operations. The spinner is started at the beginning of command execution and stopped before displaying results. [1] [2] [3] [4] [5]

Resource Loading Enhancements:

• Refactors the Resources loader in tailor/resource.go to accept functional options, allowing selective loading of applications, pipelines, TailorDBs, and state flows. Adds support for loading resolver execution results since a specified time, which is necessary for coverage analysis. [1] [2] [3] [4] [5] [6] [7] F8bfd94dL8R8)

Dependency Updates:

• Adds new dependencies: github.com/briandowns/spinner for the spinner, and github.com/k1LoW/duration for parsing duration strings in the coverage command. Updates go.mod accordingly.

Minor Cleanups:

• Minor code style and import improvements for maintainability. [1] [2]

Let me know if you'd like a walkthrough of how the new coverage feature works or how to use the new resource loading options!

[github-actions]

Code Metrics Report

Coverage	Code to Test Ratio
32.5%	1:1.7

Code coverage of files in pull request scope (20.6%)

Files	Coverage
cmd/coverage.go	0.0%
cmd/lint.go	0.0%
cmd/metrics.go	0.0%
cmd/root.go	0.0%
tailor/coverage.go	91.4%
tailor/metrics.go	100.0%
tailor/resource.go	0.0%

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Reported by octocov