add argentine speed exceptions

[gedankenstuecke]

Issue

Tries to close #7285 by adding the corresponding exceptions in line with the Article 51 of the local traffic laws.

What issue is this PR targeting? If there is no issue that addresses the problem, please open a corresponding issue and link it here.

Tasklist

• [x] CHANGELOG.md entry (How to write a changelog entry)
• [ ] update relevant Wiki pages
• [ ] add tests (see testing documentation)
• [ ] review
• [ ] adjust for comments

Requirements / Relations

Link any requirements here. Other pull requests this PR is based on?

[frodrigo]

ar:rural looks to have very few usage https://taginfo.openstreetmap.org/search?q=maxspeed%3Dar%3Arural

[country code]:[where] is used for implicit speed limit. But it looks like to me that not used for AR, eg. comparing with AT. https://wiki.openstreetmap.org/wiki/Key:maxspeed

It rather looks like to me that AR is on the maxspeed per highway type schema ?

[gedankenstuecke]

Yeah, the urban one is more common (https://taginfo.openstreetmap.org/search?q=maxspeed%3Dar%3Aurban) and is what triggered my PR, as osmose kept giving false-positives and in my PR over there it was suggested to also adapt it here, see https://github.com/osmose-qa/osmose-backend/pull/2635 :)