feat: Add the unreal2 protocol (#124)

* WIP: Add unreal2 protocol

* Add/Update badge

* protocols/unreal2: Update doc comments and TODOs

* protocols/unreal2: Don't pre-allocate as many bot players

* protocols/unreal2: Use "encoding-rs" for decoding unreal2 strings

* Add/Update badge

* protocols/unreal2: Add constants for player pre-allocation.

Also improve some doc comments and update PACKET_SIZE.

* protocols/unreal2: Early break when enough players have been parsed

Add a fast-path to avoid waiting for packet timeout when we have parsed
as many players as specified in the server info packet.

* protocols/unreal2: Use HashSet to store mutators

* protocols/unreal2: Handle server sending multiple values for a rule

* protocols/unreal2: Add GatheringSettings to control what to query

GatheringSettings allows skipping querying rules and/or players which
can make the query return much faster. This also required moving each
individual query into its own helper.

* protocols/unreal2: Add more derives to types

* protocols/unreal2: Simplify ServerInfo::parse()

Co-Authored-By: CosminPerRam <cosmin.p@live.com>

* Docs: Add unreal2 protocol documentation

I used a website to generate the markdown RESPONSES table, the save file
from this website is included to make updating the table easier in the
future.

https://www.tablesgenerator.com/markdown_tables

* Add/Update badge

* protocols/unreal2: Use the correct encoding for UCS2 strings

* Docs: Remove unnecessary TGN file

---------

Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: CosminPerRam <cosmin.p@live.com>

src/protocols/unreal2/mod.rs

@@ -0,0 +1,54 @@
+/// The implementation.
+pub mod protocol;
+/// All types used by the implementation.
+pub mod types;
+
+pub use protocol::*;
+pub use types::*;
+
+/// Generate a module containing a query function for a valve game.
+///
+/// * `mod_name` - The name to be given to the game module (see ID naming
+///   conventions in CONTRIBUTING.md).
+/// * `pretty_name` - The full name of the game, will be used as the
+///   documentation for the created module.
+/// * `default_port` - Passed through to [game_query_fn].
+macro_rules! game_query_mod {
+    ($mod_name: ident, $pretty_name: expr, $default_port: literal) => {
+        #[doc = $pretty_name]
+        pub mod $mod_name {
+            crate::protocols::unreal2::game_query_fn!($default_port);
+        }
+    };
+}
+
+pub(crate) use game_query_mod;
+
+// Allow generating doc comments:
+// https://users.rust-lang.org/t/macros-filling-text-in-comments/20473
+/// Generate a query function for a valve game.
+///
+/// * `default_port` - The default port the game uses.
+macro_rules! game_query_fn {
+    ($default_port: literal) => {
+        crate::protocols::unreal2::game_query_fn! {@gen $default_port, concat!(
+        "Make a Unreal2 query for with default timeout settings and default extra request settings.\n\n",
+        "If port is `None`, then the default port (", stringify!($default_port), ") will be used.")}
+    };
+
+    (@gen $default_port: literal, $doc: expr) => {
+        #[doc = $doc]
+        pub fn query(
+            address: &std::net::IpAddr,
+            port: Option<u16>,
+        ) -> crate::GDResult<crate::protocols::unreal2::Response> {
+            crate::protocols::unreal2::query(
+                &std::net::SocketAddr::new(*address, port.unwrap_or($default_port)),
+                &crate::protocols::unreal2::GatheringSettings::default(),
+                None,
+            )
+        }
+    };
+}
+
+pub(crate) use game_query_fn;