Set Google Analytics and GSA DAP to preconnect loading

[curt-mitch-census]

Pull Request

Description

Sets analytics scripts (Google Analytics and GSA's Digital Analytics Program) to preconnect to load earlier in page build process. Addresses: https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/.

Also removes the no-longer-maintained jekyll-assets gem as its rack dependency has multiple Dependabot alerts: https://github.com/XDgov/xd.gov/security/dependabot.

Related Issue

• Resolves https://github.com/XDgov/us-pets-lab/issues/25

Changes Made

• Change script loads in head tag.
• Removes jekyll-assets gem and its dependencies

Screenshots (if applicable)

N/A

Checklist

• I have read the CONTRIBUTING.md document.
• My code follows the project's coding standards.
• I have added tests that prove my fix is effective or that my feature works.
• All new and existing tests passed.
• I have updated the documentation accordingly.
• The title of my pull request is a short description of the changes.
• My pull request is assigned to the appropriate milestone.