Add Drush Command for Testing Schema Validation

Problem/Motivation

When working with Patternkit and the underlying pattern schemas, it can sometimes be difficult to debug specifically why some block content may be failing validation. The goal of this issue is to add tooling to ease the process of debugging this scenario.

One possible idea for this could be:

• Add a new Drush command: patternkit:validate
• Expect a pattern name argument for validation against
• Accept content input for validation
• Output all available validation output

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

• New Drush command: patternkit:validate

API changes

None

Data model changes

None