Extend interface

Reinstated the file checks in php_crack_checkpath()
Added crack_fascistcheck() interface to call FascistCheck() from cracklib

Support PHP 7.x and 8.x

Recent cracklib versions have different dictionary format from what the internal libcrack code have been using.
Dropped the internal libcrack copy and link to the external cracklib.

Add support for PHP 7.x and 8.x and drop support for PHP 4.x and 5.x at the same time.

Dropped the notion of a "default open dictionary" which was always the last opened one and just complicated things.
Instead, made the argument to crack_opendict() optional so the global configuration "crack.default_dictionary" can be used.

Reordered the arguments to crack_check() so the dictionary resource became the first argument and mandatory.