Allow to configure per-namespace persistence for process indicators, so
that Central wouldn't need to store information, which never will be used.

It could be configured via DynamicConfig of the cluster configuration in
the form:

```
message RuntimeDataControl {
  string namespace_filter = 1;
  bool exclude_openshift = 2;
  bool persistence = 3;
}
```

Where `namespace_filter` allows to specify a custom regex to filter out
processes by matching namespace, `exclude_openshift` instructs Central to
exclude anything from openshift-* namespaces, and `persistence` can be used to
disable storing process indicators at all.