Allow for password less command lines

[aadant]

Example usage

provided that

• ./clickhouse-client.xml exists
• ~/.my.cnf exists

this should work

python db_compare/clickhouse_table_checksum.py --clickhouse_host  host--clickhouse_database db  --tables_regex table --exclude_columns _version,is_deleted --sign_column ""

python db_compare/mysql_table_checksum.py --mysql_host host  --mysql_database db --tables_regex table  --max_date_value 2283-11-11

python db_load/clickhouse_loader.py --clickhouse_host clickhouse-bi-dev --clickhouse_database data_types --dump_dir /home/aadant/dbdumps/data_types  --clickhouse_port 9000 --threads 16  --mysql_source_database data_types --mysqlshell  --rmt_delete_support