doc: add flow API features tables

doc: add flow API features tables

The NICs overview table lists all supported features per driver.
There was a single row for "Flow API",
although rte_flow is composed of many items and actions.

The row "Flow API" is replaced with two new tables for items and actions.

Also, since rte_flow is not implemented in all drivers,
it would be ugly to add empty sections in some files.
That's why the error message for missing INI section is removed.

The lists are sorted alphabetically.
The extra files for some VF and vectorized data paths are not filled.

Signed-off-by: Asaf Penso <asafp@nvidia.com>
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Kiran Kumar K <kirankumark@marvell.com>
---
v6 changes:
	- rebase/update
	- remove deprecated shared action