Moodle 4.4: Failure due to new Hooks API

[opitz]

When running with Moodle 4.4 with debugging set to developer the following errors are shown:

Callback before_http_headers in local_analytics component should be migrated to new hook callback for core\hook\output\before_http_headers
and

Callback before_footer in local_analytics component should be migrated to new hook callback for core\hook\output\before_footer_html_generation
From Moodle 4.4 a new Hooks API should be used:
https://moodledev.io/docs/4.4/apis/core/hooks