databases/cego: update 2.51.1 -> 2.51.3, devel/lfcbase: update 1.19.0 -> 1.19.1

lfcbase:

• BigDecimal::div null value check

cego:

• CegoFactor::toChain to add braces for condition case
• CegoSelect::initAggregation, for sum and avg aggregation, aggregation value is initialized with 0 and appropriate datatype ( instead of null value ). This leads to numeric result 0 in case of empty result sets ( instead of null value )