optimize performance of invoking map helper functions

[saxena-anurag]

Currently all the map related helper functions (lookup, update, delete, etc.) are invoked via ebpf_map_metadata_tables (which contains function pointers for each map type).

This design helps keep the code clean but prohibits any inlining (hence any performance improvements) of these functions.

This issue it to change the design / de-virtualize map related helper functions that will allow these functions to be possibly inlined for better performance.

[shankarseal]

decreasing priority as we have made some changes to improve performance already around map lookup. For the next set of innovations, we await SPGO data.