NETOBSERV-1617: reuse flow filter capability with pcap feature (#359)

* NETOBSERV-1617: reuse flow filter capability with pcap feature

rename all flow filters to just filter to allow reuse the same configs
modify pca to use filter config
update userspace, examples and doc

Signed-off-by: Mohamed Mahmoud <mmahmoud@redhat.com>

* Allow sampling configs to be applied for PCA

Signed-off-by: Mohamed Mahmoud <mmahmoud@redhat.com>

---------

Signed-off-by: Mohamed Mahmoud <mmahmoud@redhat.com>