docker and fedora support and datetime fixes

[ipitio]

This PR reflects the changes in the Sister PRs, which add Docker support while avoiding the need to maintain a fork of docker-pi-hole.

This update also introduces the breaking change of v2: Date() is no longer used in favor of Moment.js; previous tests may show an incorrect timezone offset in the web interface. Due to the previous ambiguous formatting of the date, the easiest solution is to clear history if this bothers you.

Sister PRs:

• https://github.com/arevindh/pi-hole/pull/74
• https://github.com/arevindh/AdminLTE/pull/86

Features:

• Use cron again, but now only when systemd isn't the init system
• Instructions for how to use the Script with Docker Compose
• Deprecates arevindh/docker-pi-hole
• Update the Mod from settings to avoid rebuilding
• Support Fedora-based distros (need testers!)
• Avoid using Date()

Fixes:

• Validate db before saving results
• Ensure all necessary dependencies are installed before they're needed
• Chart overlay and update
• Select results using their timezone
• Display them in local time at the correct universal time
• Getting server name and distance

Enhancements:

• Datetime is saved as UTC in RFC 3339
• HTML accessibility improvements
• Speedtests start 100% faster
• Health check shows all data from latest test
• Clarified readme
• Display number of days when all are shown