Return error if BOOL8 column-type is used with integers-to-hex

[davidwendt]

Description

Removes support to convert BOOL8 column-type to hex using cudf::strings::integers_to_hex.
Also fixed other integer to string conversions to remove this unsupported type.
Added gtests to verify an error is thrown for this case.

Closes #14232

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[ttnghia]

This PR makes me think of something similar to cudf::test::IntegralTypesNotBool in the test module. Should we have something like this:

namespace cudf {
template<typename T>
bool constexpr is_integral_not_bool() {}
....

[mythrocks]

Wow, I could have sworn we had this already. (I think I'm confusing this with a type-list in the CUDF tests.)

Thanks for adding this.

[davidwendt]

/merge