Check remote changes

[pb82]

Checks if the remote dashboard has changed, before submitting an update. This prevents the Operator from creating a new version every time a dashboard is reconciled.

[HVBE]

LGTM! We just need go-lint to be happy again

[NissesSenap]

So I took the freedom to fix the linting.
I removed nolintlint since it doesn't seem to work. We have multiple locations in the code where we use the //nolint without any explanation and all of a sudden it complains....

[NissesSenap]

@olejeglejeg could you take a look at this PR. Jsonnet should generate standard grafana json I assume.
So changing the reconciliation shouldn't create any issues, with the jsonnet implementation, right?

[NissesSenap]

As discussed offline, it would be nice to do the same for datasources.
Also, it wouldn't hurt to add a small unit test for this.

[olejeglejeg]

So changing the reconciliation shouldn't create any issues, with the jsonnet implementation, right?

Yes, it's true, since the json generation made above, it mustn't cause issues with this part.

But I have small opinion that want to clarify: I thought that behaviour of the operator does not permit any changes with dashboards except from the code and it was a requirement and target. Is it so?

This PR is changing it which can force clients to mark their dashboards as non-editable in dashboard json declaration.