Add 'ruleset' field using TypeSet with mandatory rule_number

- Add new 'ruleset' field as TypeSet alternative to 'rule' TypeList
- Make rule_number required in ruleset (no auto-numbering needed)
- Remove deprecated 'ports' field from ruleset schema
- Add ConflictsWith to prevent using both 'rule' and 'ruleset'
- Update Create, Read, Update, Delete functions to handle both fields
- TypeSet prevents spurious diffs when rules are inserted in the middle
- Add comprehensive example showing ruleset usage
- Document key differences between rule and ruleset

Add test cases for ruleset field

- Add TestAccCloudStackNetworkACLRule_ruleset_basic test
- Add TestAccCloudStackNetworkACLRule_ruleset_update test
- Both tests mirror existing rule tests but use ruleset with explicit rule_number
- All rules in ruleset tests have mandatory rule_number values
- Tests verify TypeSet behavior and rule attributes
- Ensures ruleset field works correctly for create and update operations

Author: bhouse-nexthop