PHP 8.1 & Coding style & Production build

[tg666]

• minimum supported PHP version is now 8.1
• improved coding style
  • new Php-Cs-Fixer config (lowercase true/false/null, four spaces instead of tabs, imports ordering etc.)
  • removed unnecessary phpdoc comments
  • replaced typed array syntax from x[] to array<x> in phpdoc comments
  • promoted constructor properties
• replaced development docker images with the new unit and cli images from 68publishers/php
• added production docker images build. Both commands outputs two images - 68publishers/cmp:app-<version> and 68publishers/cmp:worker-<version>
  • $ make build.local.<version> - stores images locally
  • $ make build.multiarch.<version> - builds images for AMD and ARM architectures and pushes them to the DockerHub repository