* src/context.h (enum class RandomMode): Deprecate.
(generateRandomBytes): Deprecate overload taking RandomMode parameter.
* src/context.h, src/context.cpp (generateRandomBytes): New overload
taking only size_t parameter.
(generateRandomZBase32String): New.
* src/randomresults.h (RandomZBase32StringResult): New.
* tests/run-genrandom.cpp (main): Use generateRandomZBase32String
instead of deprecated generateRandomBytes.