pfSense

Fix #6463 Dest net alias matching on page load

Do not set destination field to use customarray
Note: dstbeginport_cust does not exist on this page, so I got removed it here also to avoid future confusion.

Fix #6460 Interface mismatch apply changes button

Rework pkg_mgr_install.php:

- Stop using id parameter for additional packages, keep using it only
for firmware upgrades
- Created to control variables $completed and $confirmed to check all
the stages and make it easy to understand what is happening
- Stop using $pkgid and use $pkgname instead...

Fix variable name s/POST/_POST/ and also parameter name s/complete/completed/

Fix indent

Improve readability

Improve readability

Simplify mode parameter validation

Remove redundant check since pkgcancel is never set

Validate mode parameter and use sanitized variable on other places