LibSQL: Support 64-bit integer values and handle overflow errors

Currently, integers are stored in LibSQL as 32-bit signed integers, even
if the provided type is unsigned. This resulted in a series of unchecked
unsigned-to-signed conversions, and prevented storing 64-bit values.
Further, mathematical operations were performed without similar checks,
and without checking for overflow.

This changes SQL::Value to behave like SQLite for INTEGER types. In
SQLite, the INTEGER type does not imply a size or signedness of the
underlying type. Instead, SQLite determines on-the-fly what type is
needed as values are created and updated.

To do so, the SQL::Value variant can now hold an i64 or u64 integer. If
a specific type is requested, invalid conversions are now explictly an
error (e.g. converting a stored -1 to a u64 will fail). When binary
mathematical operations are performed, we now try to coerce the RHS
value to a type that works with the LHS value, failing the operation if
that isn't possible. Any overflow or invalid operation (e.g. bitshifting
a 64-bit value by more than 64 bytes) is an error.

Userland/Libraries/LibSQL/Heap.h

@@ -33,7 +33,7 @@ class Heap : public Core::Object {
     C_OBJECT(Heap);
 
 public:
-    static constexpr inline u32 current_version = 2;
+    static constexpr inline u32 current_version = 3;
 
     virtual ~Heap() override;