clarify licenses and add cargo deny

flake.nix

@@ -82,6 +82,7 @@
         devShells.default = mkShell {
           buildInputs = [
             mosquitto
+            cargo-deny
             rust
             rust-analyzer
             sea-orm-cli
@@ -126,12 +127,6 @@
             strictDeps = true;
             doCheck = false;
 
-            OPENSSL_STATIC = "1";
-            OPENSSL_LIB_DIR = "${pkgsCross.pkgsStatic.openssl.out}/lib";
-            OPENSSL_INCLUDE_DIR = "${pkgsCross.pkgsStatic.openssl.dev}/include";
-
-            # Required because ring crate is special. This also seems to have
-            # fixed some issues with the x86_64-windows cross-compile :shrug:
             TARGET_CC = "${pkgsCross.stdenv.cc}/bin/${pkgsCross.stdenv.cc.targetPrefix}cc";
 
             CARGO_BUILD_TARGET = rustTarget;
@@ -139,11 +134,6 @@
               "-C"
               "target-feature=+crt-static"
 
-              # -latomic is required to build openssl-sys for armv6l-linux, but
-              # it doesn't seem to hurt any other builds.
-              # "-C"
-              # "link-args=-static -latomic"
-
               "-C"
               "linker=${TARGET_CC}"
             ];