Update module to follow DAP Guidelines

Created issue fork with the added parameters for async => true and header => true.

Initial testing of the issue fork plain diff patch:

1) Install module:
composer require 'drupal/usfedgov_google_analytics:^2.x-dev'

2) Enable:
drush en usfedgov_google_analytics

3) On admin page:
/admin/config/system/usfedgov_google_analytics

Add Agency (and optionally here Sub Agency)

4) Log out (code will not display for logged in users):
Confirm the code included just before closing tag at bottom of page HTML source:

// Test the patch/changes:
1) Include the plain diff patch file in composer.json:

"drupal/usfedgov_google_analytics": {
"3467630: Update module to follow DAP Guidelines": "https://git.drupalcode.org/project/usfedgov_google_analytics/-/merge_req..."
},

2) Apply patch:
composer install

3) Confirm code is now being included inside tag and includes "async" attribute:

Repeat above tests with Library option "Load Analytics library from CDN" switched off, with Minified selected and again with Original selected.