nat: T6365: remove warnings for negated interface selections by name (backport #3482)

[mergify]

Change Summary

Avoids spam of invalid warnings when a negated interface name is used.

...
WARNING: NAT interface "!bond0.2" for destination NAT rule "430" does
not exist!
WARNING: NAT interface "!bond0.2" for destination NAT rule "450" does
not exist!
WARNING: NAT interface "!bond0.2" for destination NAT rule "470" does
not exist!
WARNING: NAT interface "!bond0.2" for destination NAT rule "490" does
not exist!
WARNING: NAT interface "!bond0.2" for destination NAT rule "510" does
not exist!
...

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

https://vyos.dev/T6365

Related PR(s)

none

Component(s) name

• nat source
• nat destination

Proposed changes

Added code to parse negation (in a similar manner groups are used).

How to test

set nat destination rule 10 description 'DNS'
set nat destination rule 10 destination address 10.0.0.1
set nat destination rule 10 destination port 53
set nat destination rule 10 inbound-interface name '!eth0'
set nat destination rule 10 protocol 'tcp_udp'
set nat destination rule 10 translation address 172.16.0.1

And perform a commit.

Smoketest result

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

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This is an automatic backport of pull request #3482 done by [Mergify](https://mergify.com).