Update development toolkit

[MGatner]

• Updates PHPUnit test parameters for tighter testing
• Adds Infection for mutation testing (test quality testing)
• Adds RoaveBC to detect breaking changes
• Adds Tachycardia for slow test detection and annotation
• Adds Coveralls upload to Action workflow
• Switches code style enforcement to PHP CS Fixer to match the framework (awaiting configuration)

[lonnieezell]

I'll approve it but I think we need to raise the limit on the slow tests since password/encryption is always slower if it's strong.

[MGatner]

raise the limit on the slow tests

For sure. This can be done per test class or per test method. For now it won't hurt anything (i.e. nothing "fails") until someone can go through and figure out which are actually slow tests and which will always be that way.