Database: Add hasRemediations filter to Vulnerability Report

Issue to track the database implementation work to add has_remediations filter to VulnerabilityReport.

So that the following CQL is supported see: #358638 (closed)

query {
  project(fullPath: "gitlab-org/gitlab") {
    vulnerabilities(reportType:DEPENDENCY_SCANNING, hasRemediations:true) {
      nodes {
        hasRemediations
      }
    }
  }
}

Implementation plan:

• database MR 1: Add has_remediations column to vulnerability_reads table
• database MR 2: Update trigger in database for has_remediations field
  • Use the trigger for other vulnerability fields as an example for this
• database MR 3: Backfill has_remediations column with background migration and include a model validation for has_remediations to be true/false.

Non-functional requirements

• Performance: Need to see how this would affect the performance of vulnerability_reads
• Testing: New tests will need to be added
• E2E testing: Make sure e2e: package-and-test is run and govern specs are green