Added bytes type and some inference (#13061)

## Summary

This PR adds the `bytes` type to red-knot:
- Added the `bytes` type
- Added support for bytes literals
- Support for the `+` operator

Improves on #12701 

Big TODO on supporting and normalizing r-prefixed bytestrings
(`rb"hello\n"`)

## Test Plan

Added a test for a bytes literals, concatenation, and corner values

crates/ruff_python_ast/src/nodes.rs

@@ -2152,7 +2152,7 @@ impl BytesLiteralValue {
     }
 
     /// Returns an iterator over the bytes of the concatenated bytes.
-    fn bytes(&self) -> impl Iterator<Item = u8> + '_ {
+    pub fn bytes(&self) -> impl Iterator<Item = u8> + '_ {
         self.iter().flat_map(|part| part.as_slice().iter().copied())
     }
 }