Panels template conversion to twig standards

## Ready State: Yes

#### JIRA Reference: N/A
Replaced all template files with the panels plugin with twig template files.

## Requirements & Dependencies
* None

## Deployment Instructions
* Switch to branch.
* Clear all caches.

## Usage/Test Instructions
* Browse to the homepage and confirm that no error messages are thrown.
* Check error logs at /admin/reports/dblog to ensure on theme related errors or warnings are thrown.