add buildscripts for js deps

scripts/deps-docker/Dockerfile

@@ -0,0 +1,43 @@
+FROM    alpine:3.10
+WORKDIR /z
+ENV     ver_forge=0.8.5 \
+        ver_ogvjs=1.6.1
+
+# download
+RUN     apk add make g++ git bash npm patch wget tar gzip unzip \
+        && wget https://github.com/digitalbazaar/forge/archive/$ver_forge.tar.gz \
+        && wget https://github.com/brion/ogv.js/releases/download/$ver_ogvjs/ogvjs-$ver_ogvjs.zip \
+        && tar -xf $ver_forge.tar.gz \
+        && unzip ogvjs-$ver_ogvjs.zip \
+        && cd forge-$ver_forge \
+        && npm install
+
+# customize
+COPY    forge.patch /z
+
+# build forge
+RUN     cd forge-$ver_forge \
+        && patch -p1 < /z/forge.patch \
+        && npm run build \
+        && mkdir /z/dist \
+        && cp -pv dist/forge.sha512.* /z/dist
+
+# build ogvjs
+RUN     cd ogvjs-$ver_ogvjs \
+        && cp -pv \
+            ogv.js \
+            ogv-worker-audio.js \
+            ogv-demuxer-ogg.js \
+            ogv-demuxer-ogg-wasm.js \
+            ogv-demuxer-ogg-wasm.wasm \
+            ogv-demuxer-webm.js \
+            ogv-demuxer-webm-wasm.js \
+            ogv-demuxer-webm-wasm.wasm \
+            ogv-decoder-audio-opus.js \
+            ogv-decoder-audio-opus-wasm.js \
+            ogv-decoder-audio-opus-wasm.wasm \
+            ogv-decoder-audio-vorbis.js \
+            ogv-decoder-audio-vorbis-wasm.js \
+            ogv-decoder-audio-vorbis-wasm.wasm \
+            dynamicaudio.swf \
+            /z/dist