Implement more traits for UriRefBuf and UriBuf

[Luro02]

The following traits could be implemented

• FromStr
• TryFrom
  -> TryFrom<&str>
  -> TryFrom<&String>
  -> TryFrom<String> (only for UriBuf)
  -> impl<T: AsRef<UriRef>> TryFrom<T>

Most of these traits can be simply delegated to their respective function

use std::str::FromStr;

impl FromStr for UriBuf {
   type Err = ParseError;

    fn from_str(input: &str) -> Result<Self, Self::Err> { Self::from_str(input) }
}

[Luro02]

I am working on this :)

[darconeous]

Cool! Having a look now.

[darconeous]

This landed via 99a61ee.