fix: do not require recreate if system-routes property is changed

[gottliebjo]

There is now an update mechanism for changing the "system_routes" property on routing tables. Therefore it does not need to be recreated but can be updated instead.

Description

The IaaS-API now allows for the system_routes property of a routing table to be updated. Therefore we can remove the requiresReplace for it and can update the RT instead of delete and create it.

Checklist

• Issue was linked above
• Code format was applied: make fmt
• Examples were added / adjusted (see examples/ directory)
• Docs are up-to-date: make generate-docs (will be checked by CI)
• Unit tests got implemented or updated
• Acceptance tests got implemented or updated (see e.g. here)
• Unit tests are passing: make test (will be checked by CI)
• No linter issues: make lint (will be checked by CI)