Feature request: proper control over filter order with ordinals

[reegnz]

Is your feature request related to a problem? Please describe.

Currently the only way to influence the order of ClusterFilters (and namespaced filters) is to put them in alphabetical order.

Also we cannot have some clusterfilters run after the evaluation of namespaced filters. The order is fixed, first clusterfilters, then namespaced filters.

This makes it difficult to perform some final clusterfilters after all other filters are done and right before sending off to an output.

Describe the solution you'd like

Introduce an ordinal attribute to ClusterFilter and Filter CRD-s.
Ordinal should not be mandatory (for backward compatibility) and the default should be 0.

ClusterFilters should be sorted primarily by ordinal, and secondarily alphabetically.

Filters (namespaced) should be sorted primarily by ordinal and secondarily alphabetically.

Example:

ClusterFilter A: no ordinal specified
ClusterFilter B: ordinal=0
ClusterFilter C: ordinal=-10
ClusterFilter D: ordinal=10

filter chain then looks like:
C-> A -> B -> D

[reegnz]

I gave it a go and already have an initial implementation to propose, PR is up in a couple of minutes.

[reegnz]

An additional annoyance that I think I will put in a different Issue is allowing some clusterfilters to be applied AFTER namespace filters have already been applied.