VCL-1138 - make PHP code compatible with PHP 8

generally:
-added default values when processing POST or GET input data so NULL values aren't assigned
-removed calls to get_magic_quotes_gpc and stripslashes
-changed how date and time values are formatted to remove calls to strftime
-added checks for variables having NULL value before using string functions (such as strpos, strlen) on them
-for some classes, added some variable declarations to top of class

additional specifics:
help.php: changed calls to mysql_fetch_assoc to call mysqli_fetch_assoc
requests.php: modified printImageDescription to use new function htmlwrap that wraps strings without counting the characters used by html tags
utils.php:
-changed __autoload to vclAutoLoader registered with spl_autoload_register
-added doPSQuery, similar to doQuery but uses prepared statements
-added minToDaysHourMin
-added htmlwrap
-modified getVariable, getVariablesRegex, and setVariable to use doPSQuery instead of doQuery
-modified getFSlocales to use fgets and strip_tags instead of fgetss