Refactor: libcib: Cache CIB op name-to-details mappings in cib_file.c

This prevents repeated loop iterations. The table doesn't change.

This is almost identical to what we're doing in
based_common.c:cib_get_operation(). The hope is to merge cib_server_ops
and cib_file_ops in the future, using shared helper functions and some
other shared data structures.

Ref T185

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>