devtools: check flow API doc tables

devtools: check flow API doc tables

The script check-doc-vs-code.sh may be used to add
some automatic checks of the doc.

If run without any argument, a complete check is done.
The optional argument is a git history reference point
to check faster only what has changed since this commit.

In this commit, the only check is for rte_flow tables,
achieved through the script parse-flow-support.sh.
If run without a .ini reference, it prints rte_flow tables.
Note: detected features are marked with the value Y,
while the real .ini file could have special values like I.
The script allow parsing exceptions (exclude or include),
like for bnxt code which lists unsupported items and actions.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
---
v6 changes:
	- fix redundant drivers
	- ignore indirect action
	- prefix misses with a category (item or action)