Improve PHP 8.1 and Emacs 28 support

Added

• Support new PHP 8.0 and 8.1 syntax highlighting and indentation
  • [8.0] #[Attributes]
  • [8.1] readonly property (#680)
• Add php-imenu-generic-expression-default for default value or php-imenu-generic-expression
  • Add php-imenu-generic-expression-legacy for compatibility
  • Add php-imenu-generic-expression-simple for simple display
• Add php-project-project-find-function compatible with project-find-functions (#693)

Changed

• Optimized propertize process (#669)
  • Reimoplement php-syntax-propertize-function using syntax-propertize-rules
  • Make propertize PHP 8 #[Attribute] always enabled
  • Changed grouping of php-heredoc-start-re
• Re-organized php-imenu-generic-expression
  • Added Import, Constants and Properties
  • Removed Anonymous Functions
  • Renamed Named Functions to Functions
  • Renamed All Methods to Methods
  • Removed Public Methods, Protected Methods and Provate Methods
  • Unified Classes, Traits, Interfaces into Classes
• Modified regexp patterns (#681)
• Suppress compile-time warnings (#683, #690, #697)

Fixed

• Fix php-run-builtin-web-server to expand root path (#699)