vmalertmanager: ignore content of configSecret if name clashes with default

[f41gh7]

Ignores any content from secret define at cr.spec.configSecret, if it name clashes with name of the secret created by operator.

#954

[Haleygo]

But this also means we will override the original secret contents that user had, so the wrost scenario is: user predefined all the configs under secret vmalertmanager-example-config and specified secret in vmalertmanager, now operator will ignore the configs and erase them.
What about trying merging configs or changing default secret name if conflict happens?

[f41gh7]

But this also means we will override the original secret contents that user had, so the wrost scenario is: user predefined all the configs under secret vmalertmanager-example-config and specified secret in vmalertmanager, now operator will ignore the configs and erase them. What about trying merging configs or changing default secret name if conflict happens?

There is no easy way to check an owner of this secret. It's possible to use heuristic and check labels. But it's not reliable solution.

I think, it's fine to overwrite user created secret and notify about it. And it ll be more predictable behavior.

[Haleygo]

LGTM