Server Side Password Check

[Hackmastr]

Description

Check if the current password is correct server side.

Motivation and Context

Closes #595

How Has This Been Tested?

Tested in PHP 7.3.

Screenshots (if appropriate):

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.