Fixes #37925 - translate local time properly for tokens

[ianballou]

Without setting the Sequel default_timezone, the time on tokens from Foreman do not get translated to the local time on the system. This means that the postgres CURRENT_TIMESTAMP uses a different timezone from the saved expiry times on tokens.

This PR sets default_timezone to :local so that the postgres CURRENT_TIMESTAMP and the times fetched from the DB have an agreeing timezone.

To test:

1. On the smart proxy DB, change the timezone to GMT-2:

container_gateway=# alter database postgres set TIMEZONE TO 'Etc/GMT-2';
container_gateway=# alter database container_gateway set TIMEZONE TO 'Etc/GMT-2';
container_gateway=# set timezone to 'Etc/GMT-2';

2. Also change the system time for good measure:

$ timedatectl set-timezone Etc/GMT-2

3. Ensure you're logged out of the smart proxy container registry

4. Log in to the smart proxy container registry

5. See a login error about invalid username/password

6. Patch in my PR, restart foreman-proxy, see that the issue is fixed

[vsedmik]

Tested the patch manually with GMT-2, GMT-12, GMT+12 and worked well in all cases:

[vsedmik@fedora broker]$ podman login --tls-verify=false -u admin -p changeme capsule.redhat.com
Login Succeeded!
[vsedmik@fedora broker]$ podman logout capsule.redhat.com
Removed login credentials for capsule.redhat.com

Without this patch I saw:

[vsedmik@fedora broker]$ podman login --tls-verify=false -u admin -p changeme capsule.redhat.com
Error: logging into "capsule.redhat.com": invalid username/password

[chris1984]

Code looks fine and Vlad tested