Public cleanup 2

[cviebrock]

• standardize tooling and configs
• normalize composer.json and bump packages
• pretty code
• compress SVGs (not part of the package tooling or pipeline)
• disable Jenkins and switch to GH actions
• made some changes suggested by Rector:
  • switch to match
  • use str_contains where possible
  • use ?? where possible
  • use ::class where possible
  • etc.

Note

1. It's easiest to view the XML changes in isolation, or with whitespace turned off: c8513f2
2. It's also easiest to view the Rector changes in isolation: b82f440