This PR aims to simplify text creation and to reduce allocation overhead
of creating a new OwnedValue::Text. Instead of creating Rc<String> every
time you need to create a text, you just pass the string slice and the
Rc<String> is created at the end. This change, at least on my machine,
has removed a lot of variability in the benchmarking performance, while
maintaining roughly the same performance.
Closes#961