[3] Improve the logic of update-ips script

[aarnq]

Is your feature request related to a problem? Please describe.
With the work of #1582 done we're improved the functions and general handling of IPs a lot, so now we should focus on improving the logic behind it.

Describe the solution you'd like

• Better grouping of checks so that as an example all specific for SC may be under the same if statement.
• Reusable function for looking up keystone+swift endpoints.
• Reusable functions for extracting domain name and ports from endpoints.
• Simplify the logic for rclone sync.
• Moving things to functions to simplify structure and make it more digestible.

Describe alternatives you've considered
Keep current which is harder to maintain.

Definition of done:
The update-ips script is further improved.