Implement "support doc comments for internal classes and functions"

[kocsismate]

Fixes #13130

The biggest change of this PR (besides the internal structures of functions and classes) is how function entries are generated by gen_stub.php: so far the higher level macros were used (ZEND_ME , ZEND_FALIAS etc.), but since the variations we have has already started to skyrocket, I decided to go with the ZEND_RAW_FENTRY macro which is the lowest level... As we now have a decent framework for generating the arginfo.h file by taking into account older PHP versions as well, I think this change is less problematic... A random example:

#if (PHP_VERSION_ID >= 80400)
	ZEND_RAW_FENTRY("zend_test_zend_ini_parse_quantity", zif_zend_test_zend_ini_parse_quantity, arginfo_zend_test_zend_ini_parse_quantity, 0, NULL)
#else
	ZEND_RAW_FENTRY("zend_test_zend_ini_parse_quantity", zif_zend_test_zend_ini_parse_quantity, arginfo_zend_test_zend_ini_parse_quantity, 0)
#endif

(NULL stands for the doc_comment in the function entry generated for PHP 8.4+).

[kocsismate]

@iluuu1994 I slightly refactored the behavior, and now ZEND_FE and ZEND_ME is also generated if possible. This also means that I got rid of generating ZEND_FRAMELESS_FEs because this use-case also deemed to be uncommon.

When implementing this, I added support for conditional frameless func info item generation based on the PHP version compatibility requirements. I didn't commit this fix separately because it needed the PHP version compatibility info which I had just added in this PR.

[TimWolla]

and ack for ext/random.

[devnexen]

pgsql looks ok to me.

[kocsismate]

Ilija, could you have another look please?

[iluuu1994]

The C code LGTM! I didn't look closely at build/gen_stub.php.

[Girgias]

LGTM, also didn't check gen_stub too closely