Use default export templates for HTML5

Changes Emscripten SDK version to match that used to compile the default export
templates used by Godot 3.5 (in this case 3.1.14 as can be seen here:
https://github.com/godotengine/build-containers/blob/3.5/Dockerfile.javascript).

This means we no longer need to compile custom export templates when
exporting HTML5 for Godot 3.5. Exports from other Godot versions may
requiring compiling the GDNative library with a different version of the
Emscripten SDK.

- Changes renderer from GLES3 -> GLES2 and reduces MSAA level to better
  support HTML5 export.
- Updates GitHub Action to export HTML5 and upload as a build artifact.
- Adds Cypress test to smoke test HTML5 export.

misc/docker/Dockerfile

@@ -1,4 +0,0 @@
-# For convenient building of the library and gdnative export templates targeted at the javacript platform.
-FROM emscripten/emsdk:3.1.5
-RUN apt-get update && apt-get install pkg-config python3 -y
-RUN pip3 install scons

misc/export_templates/build.sh

@@ -1,41 +0,0 @@
-set -e
-
-# Parse args.
-args=$@
-while [[ $# -gt 0 ]]; do
-  key="$1"
-  case $key in
-    -t|--target)
-      target="$2"
-      shift
-      shift
-      ;;
-    *)
-      echo "Usage: ./build.sh [-t|--target <release|debug>]";
-      exit 128
-      shift
-      ;;
-  esac
-done
-# Set defaults.
-target=${target:-debug}
-
-# Get the absolute path to the directory this script is in.
-EXPORT_TEMPLATES_DIR="$( cd "$(dirname "$0")" >/dev/null 2>&1 ; pwd -P )"
-
-# Update git submodules.
-GODOT_DIR=${EXPORT_TEMPLATES_DIR}/godot
-if [ -z "$(ls -A -- "$GODOT_DIR")" ]; then
-	cd ${EXPORT_TEMPLATES_DIR}
-	git submodule update --init --recursive -- $GODOT_DIR
-fi
-
-# Use Docker to build HTML5 GDNative export templates.
-UID_GID="0:0" docker-compose build javascript
-UID_GID="$(id -u):$(id -g)" docker-compose run -e TARGET=$target javascript
-
-if [ "$target" == "debug" ]; then
-	mv godot/bin/godot.javascript.debug.gdnative.zip godot/bin/webassembly_gdnative_debug.zip    
-else
-	mv godot/bin/godot.javascript.opt.gdnative.zip godot/bin/webassembly_gdnative_release.zip
-fi

misc/export_templates/docker-compose.yaml

@@ -1,12 +0,0 @@
-services:
-  javascript:
-    build: ../docker
-    user: ${UID_GID}
-    volumes:
-      - ./godot:/src
-    command:
-      - /bin/bash
-      - -c
-      - |
-        cd src
-        scons platform=javascript tools=no gdnative_enabled=yes target=$${TARGET} -j$$(nproc)

misc/export_templates/godot

@@ -1 +0,0 @@
-Subproject commit 419e713a29f20bd3351a54d1e6c4c5af7ef4b253

misc/export_templates/readme.txt

@@ -1 +0,0 @@
-HTML5 GDNative export templates are not provided, this is just a convient script/docker-compose file for building them locally.