Improve `rancher/charts` bump interactions

[mallardduck]

Per title, this is now tracking an effort to improve the way all teams interact with this image.
Currently our team has implemented some pretty cool automations for the ob-team-charts -> rancher/charts automation that keeps the proper tag in use on charts. Essentially we need to improve this for other teams next.

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There are 2 ways we can do that, but only one is really worth it to fix CVEs - the other is most helpful to end-users potentially though.

1. Add a rancher/charts automation matching the one we have for ob-team-charts
2. Add a new Setting for kuberlr-kubectl and manage like rancher/shell tag setting - then inject on all charts.

These both solve the issue in different and potentially complementary ways. However the risk would be that if we do both then assume:

1. rancher ships with version X,
2. OOB chart release ships version X+1
3. Rancher will still want to inject version X (downgrading the version)

We would need to add something to juggle the versions to pick the right one.

With that in mind we should pursue option 1 first, then later consider 2 and all the implications it could have.