When converting a double larger or equal to math.MaxInt64 to an integer, it previously overflowed silently. It now returns an explicit error.
This fixes along the way, the math.abs(-9223372036854775808) issue.
We now have a literal representation for BLOBs. Any string literal starting
with '\x' is parsed as an hex encoded blob. This mimics PostgreSQL's behavior.
```sql
SELECT '\xAAFF';
```
This replaces the Value struct by an interface to allow us to override some
values behavior in the future.
It also introduces a new package types, which contains type definitions, comparison,
and arithmetics.
Concerning encoding, Genji now only uses on type of encoding for values. This simplifies
indexing logic as well as table access in general.
Previously, expressions and params were evaluated
during the planning phase. This change builds the query
plan without evaluating params and expressions
which are then evaluated only during the execution phase.
This was used to buffer parsed expressions to be used as keys in the
projected documents.
This is no longer necessary, as every expression can now be stringified.
