Return PHP 7.3 compatibility, replace eval() with AST

[msaladna]

Presently composer.lock is generated against PHP 8.0.2+, which breaks library installation against PHP 7.3/4. Reduce third-party versioning to preserve this guarantee.

[msaladna]

Replaced eval() usage with nikic's AST parser. This handles Joomla 2-5 and can be easily extended without finagling with class declarations. A few other changes were implemented, annotated in the commit log.

object(Joomlatools\Console\Joomla\VersionSniffer)#271 (5) {
  ["release"]=>
  string(5) "3.6.5"
  ["major"]=>
  int(3)
  ["minor"]=>
  int(6)
  ["patch"]=>
  int(5)
  ["extra"]=>
  string(0) ""
}

object(Joomlatools\Console\Joomla\VersionSniffer)#271 (5) {
  ["release"]=>
  string(5) "5.0.0"
  ["major"]=>
  int(5)
  ["minor"]=>
  int(0)
  ["patch"]=>
  int(0)
  ["extra"]=>
  string(0) ""
}

object(Joomlatools\Console\Joomla\VersionSniffer)#271 (5) {
  ["release"]=>
  string(9) "4.3.1-rc1"
  ["major"]=>
  int(4)
  ["minor"]=>
  int(3)
  ["patch"]=>
  int(1)
  ["extra"]=>
  string(3) "rc1"
}

object(Joomlatools\Console\Joomla\VersionSniffer)#269 (5) {
  ["release"]=>
  string(6) "2.5.27"
  ["major"]=>
  int(2)
  ["minor"]=>
  int(5)
  ["patch"]=>
  int(27)
  ["extra"]=>
  string(0) ""
}