feat: add the default gc config

[chlins]

This pull request introduces changes to support a default garbage collection (GC) configuration in the database layer. The most important updates include adding new constants and types for GC configuration, seeding the database with a default GC configuration, and importing necessary dependencies.

Database enhancements:

• manager/database/database.go: Updated the seed function to create a default GC configuration in the database if it does not already exist. This involves defining default TTL values for audit and job configurations, serializing them to JSON, and storing them in the Config table.

Configuration model updates:

• manager/models/config.go: Added constants for the GC configuration name (ConfigGC) and default TTL values (DefaultGCJobTTL, DefaultGCAuditTTL). These values are used to define the default behavior for GC operations.
• manager/models/config.go: Introduced new types GCConfig, GCAuditConfig, and GCJobConfig to represent the structure of the GC configuration, including TTL fields for audit and job settings.

Dependency updates:

• manager/database/database.go: Imported the encoding/json package to handle JSON serialization of the GC configuration.

Description

Related Issue

#3811

Motivation and Context

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 23 lines in your changes missing coverage. Please review.
✅ Project coverage is 34.37%. Comparing base (0cfd020) to head (0ac6e45).
⚠️ Report is 215 commits behind head on main.

Files with missing lines	Patch %	Lines
manager/database/database.go	0.00%	23 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3987      +/-   ##
==========================================
- Coverage   34.40%   34.37%   -0.03%     
==========================================
  Files         341      341              
  Lines       40072    40095      +23     
==========================================
- Hits        13787    13783       -4     
- Misses      25377    25403      +26     
- Partials      908      909       +1     

Flag	Coverage Δ
unittests	34.37% <0.00%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
manager/database/database.go	0.00% <0.00%> (ø)

... and 3 files with indirect coverage changes

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[gaius-qi]

LGTM

[Liam-Zhao]

LGTM