box: make UUID part of SCALAR

Prior to this patch, UUID was not part of SCALAR. However, this should
be changed to comply with the RFC "Consistent Lua/SQL types".

Closes #6042

@TarantoolBot document
Title: UUID is now part of SCALAR

The UUID field type is now part of the SCALAR field type. This means
that now values of type UUID can be inserted into the SCALAR field, and
these values can participate in the sorting of the SCALAR fields. The
order is as follows: boolean < number < string < varbinary < uuid.