Add Rust TLS Feature Flag For opentelemetry-http (#1638)

Similar issue to what #472 but for opentelemetry-http
Please provide a brief description of the changes here.
Added new feature flag for the opentelemetry-http crate to enable rustls instead of openssl

Author: LuisOsta

opentelemetry-http/CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 
 ## vNext
+- Add feature flag enabling users to configure `reqwest` usage to use rustls via `reqwest/rustls-tls` feature flag
 
 ## v0.11.0
 

opentelemetry-http/Cargo.toml

@@ -9,6 +9,9 @@ license = "Apache-2.0"
 edition = "2021"
 rust-version = "1.65"
 
+[features]
+reqwest-rustls = ["reqwest", "reqwest/rustls-tls-native-roots"]
+
 [dependencies]
 async-trait = { workspace = true }
 bytes = { workspace = true }