plugin/ssa_extract.c: Move more code into ssa_db_extract_alloc_tbls method

Moved allocation of guid_to_lid/link/port tables
into separate method - ssa_db_extract_alloc_tbls.

Signed-off-by: Ilya Nelkenbaum <ilyan@mellanox.com>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>
plugin/ssa_extract.c: moving node_tbl_rec extract to separate function

Signed-off-by: Ilya Nelkenbaum <ilyan@mellanox.com>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>