python3: Fix sqlite3 module

python3: Fix sqlite3 module

This patch fixes several problems that would cause compilation errors
when the sqlite3 module is selected. This patch fixes the name of
the module to sqlite3 as it defined in the oficial documentation, adds
missing export in module_config.c and defines passes two symbols
MODULE_NAME and SQLITE_OMIT_LOAD_EXTENSION.

Signed-off-by: Vlad Badoiu <vlad_andrei.badoiu@upb.ro>
Reviewed-by: Cezar Craciunoiu <cezar.craciunoiu@gmail.com>
Approved-by: Razvan Deaconescu <razvan.deaconescu@cs.pub.ro>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Pull-Request: #4