Argument-dependent lookup will not find to_string() overloads in the global
namespace if the argument and the caller are in other namespaces.
Move these to_string() overloads to std:: so ADL will find them.
Found by clang.
This patch adds an utility function to rename an identifier
occurring in a cql3 relation. This function will be used when renaming
an identifier in a view's where clause.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>