tpl: do not use core.current_url

[glensc]

it breaks configurations that are behind proxy
or rewrite rules are being applied

for example i route based on ab cookie value users to "production" instance or "dev" instance using the same urls.

and pages that use current_url get exposed to the "real" url behind the scenes.

rest of the templates use rel_url or base_url, so to cleanup current_url is good for consistency as well.

the same applies for $_SERVER['PHP_SELF']

• {$core.current_url}
• $_SERVER['PHP_SELF']