MEDIUM: stick-table: add the new arrays of gpc and gpc_rate

MEDIUM: stick-table: add the new arrays of gpc and gpc_rate

This patch adds the definition of two new array data_types:
'gpc': This is an array of 32bits General Purpose Counters.
'gpc_rate': This is an array on increment rates of General Purpose Counters.

Like for all arrays, they are limited to 100 elements.

This patch also adds actions and fetches to handle
elements of those arrays.

Note: As documented, those new actions and fetches won't
apply to the legacy 'gpc0', 'gpc1', 'gpc0_rate' nor 'gpc1_rate'.