Extend the Rancher/Docker and k8s providers to support custom Error pages

[dbsanfte]

Vis a vis:
#2035 (comment)

It looks like the only way to use custom Error pages right now is via file configuration, which isn't feasible for the Rancher/Docker provider (including k8s provider too as a courtesy).

Can we get these configurable in labels please? We'd really like to use them.

[ldez]

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[dbsanfte]

@ldez

This is a feature request.

[emilevauge]

Sorry, this was closed a bit too quickly

[ldez]

@dbsanfte Every time someone does not respect the issue's template, a little bunny dies.

Please edit your issue description to respect the issue template as much as possible.