OVH: fixing cache refresh issues and duplicates processing

[nmaupu]

Description

• Cache was not updated when a change occurred which resulted in a change to be redone at each loop
• OVH DNS can have multiple times the exact same entry. Make sure we process all the IDs (instead of picking indefinitely the first one and trying to delete it multiple times resulting in 404).
• Using soft errors instead of hard errors

This PR Fixes all that and make the provider more resilient (all the errors were not soft resulting in the binary to exit).
This also makes #4844 irrelevant as this bug was produced by :

• the cache not being refreshed after changes.
• the list of duplicates not being processed correctly.

Checklist

• Unit tests updated
• End user documentation updated

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[alexandrevilain]

Thanks @nmaupu !
We were having many issues since 0.15.0 with external-dns crashlooping. I tried a custom build based on your work and it works well.

[k8s-ci-robot]

@alexandrevilain: changing LGTM is restricted to collaborators

In response to this:

Thanks @nmaupu !
We were having many issues since 0.15.0 with external-dns crashlooping. I tried a custom build based on your work and it works well.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: alexandrevilain
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[nmaupu]

/assign @Raffo

[nmaupu]

Ping @mloiseleur @szuecs