Token based login system

[Groruk]

Description

Switch from an session based login to a token based system.

This PR also contains changes for:

• auto generating password
• replacing SB_WP_URL with a Host class that auto resolves paths instead of users setting it manually
• some general code cleanup

These changes affect
#553
#514
FIX #350
FIX #487
(FIX #374)
(FIX #326)

Motivation and Context

While the implementation of the 'Session Based' login model in SourceBans++ wasn't the best from the get go and we could improve that one a bit through more work, it would most likely die in one of the later releases of SourceBans++.
A token based login system would give us a lot more access control in the future, but also aid in the creation of API tokens.

What is still to do?

• Rewrite lost password function
• Write steam auth handler
• Add button for password generation
• Add auth token maxlife values to settings page
• Scrap quote system
• Address Display message when SteamID login fails #487
• Change min version of PHP in installer to 7.1
• Check for openSSL during installation
• Test Code Completely

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.

[geominorai]

Someone's been a busy boy. 👀