src/db_utils/config.py: add cpu variable. src/db_utils/__main__.py: add the function to fill frequency table

src/db_utils/populate_database.py - src/db_utils/config.py: modification of check_table_name, it now checks if the table name given exists in the database, not if it presents in Config.tables (so, this last variable was removed)

src/db_utils/config.py: modification of prefixes gin to cin in Config.table + creation of Config.bed_exon and Config.bed_gene variable

src/db_utils/config.py: modification of Config.db_file and Config.output + deletion of LOGGING_CONFIG, logging_def and LoggingLevelError