[C++][Python][Compute] Number to string hex conversion

[asfimport]

Add compute function to support integer to string hexadecimal conversion, similar to Python's hex() function.

>>> hex(10)
'0xa'

Reporter: Eduardo Ponce / @edponce

Related issues:

• [C++] String algorithm library for StringArray/BinaryArray (is a child of)
• [C++][Python][Compute] String hex to numeric conversion and bit shifting (relates to)

_{Note: This issue was originally created as ARROW-13774. Please see the migration documentation for further details.}

[asfimport]

Eduardo Ponce / @edponce:
Arrow already supports some hex parsing support by HexEncode but it is not exposed as a compute function.