Update this plugin to the latest official template

[lisachenko]

This plugin hasn't been touched for almost 8 years and still works somehow.

Need to follow https://plugins.jetbrains.com/docs/intellij/plugin-github-template.html and https://github.com/JetBrains/intellij-platform-plugin-template to configure entire CI/CD pipeline and simplify future maintenance.

Main target is to add support for matching by native Php Attributes, available now via PhpAttributeImpl + PhpAttributesListImpl.

[lisachenko]

@wbars Hello ) Could you please point me to the direction how to make such old code running again? Is there any migrator script that can do the work to migrate to the template?

(I'm not Java developer and it will be problematic to refresh in my memory every single piece of this plugin after 8 years)