lang/php80: Adding MySQL 8.0 'caching_sha2_password' support in php80

[bofh]

Summary

This patch adds an OPTION for adding 'caching_sha2_password' (Default Password mechanism in MySQL >= 8.0) in php80. If the OPTION MYSQL80 is selected it will build openssl module with base PHP including mysqlnd. This will also prevent php80-openssl module from being installed in the future. php80-mysqli and php80-pdo_mysql will use mysqlnd.

Test Plan

portmaster --force-config databases/php80-mysqli

Select MYSQL80 in php80 OPTIONS menu.