Move the `cactid` function `db_check_reconnect()` to `lib/database.php` for other service oriented scripts

[TheWitness]

Describe the Enhancement

The cactid.php service script has a function that checks the status of the database and if the connection was broken for some reason, cactid.php will attempt to re-establish it. This should be a core Cacti function and not kept to itself in cactid.php