Switch to rustls and webpki-roots (#30025)

This change replaces OpenSSL with rustls and also the manually curated
CA certs file with webpki-roots (effectively the same thing, but as a
crate).

Generally speaking the design of the network stack is the same. Changes:

- Code around certificate overrides needed to be refactored to work with
  rustls so the various thread-safe list of certificates is refactored
  into `CertificateErrorOverrideManager`
- hyper-rustls takes care of setting ALPN protocols for HTTP requests,
  so for WebSockets this is moved to the WebSocket code.
- The safe set of cypher suites is chosen, which seem to correspond to
  the "Modern" configuration from [1]. This can be adjusted later.
- Instead of passing a string of PEM CA certificates around, an enum is
  used that includes parsed Certificates (or the default which reads
  them from webpki-roots).
- Code for starting up an SSL server for testing is cleaned up a little,
  due to the fact that the certificates need to be overriden explicitly
  now. This is due to the fact that the `webpki` crate is more stringent
  with self-signed certificates than SSL (CA certificates cannot used as
  end-entity certificates). [2]

1. https://wiki.mozilla.org/Security/Server_Side_TLS
2. https://github.com/briansmith/webpki/issues/114

Fixes #7888.
Fixes #13749.
Fixes #26835.
Fixes #29291.

1 files changed, 0 insertions, 16 deletions

diff --git a/components/net/build.rs b/components/net/build.rs
deleted file mode 100644
index 4a75c1b4bbb..00000000000
--- a/components/net/build.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
-
-fn main() {
-    let version =
-        std::env::var("DEP_OPENSSL_VERSION_NUMBER").expect("missing DEP_OPENSSL_VERSION_NUMBER");
-    let actual = u64::from_str_radix(&version, 16).unwrap();
-    let minimum = 0x10101000;
-    if actual < minimum {
-        panic!(
-            "Your OpenSSL version is older than 1.1.1 ({:x}), you have: {:x}",
-            minimum, actual
-        );
-    }
-}