Support GPU in libgrape-lite (alibaba#83)

* support GPU in libgrape-lite.

Author: mengke-mk

.github/workflows/cuda.yml

@@ -0,0 +1,23 @@
+name: CUDA CI
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [self-hosted]
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          submodules: true
+      - name: Build
+        run: |
+          mkdir build
+          cd build
+          cmake ..
+          make
+      - name: APP Test
+        run: |
+          ./misc/cuda_app_tests.sh

.gitmodules

@@ -0,0 +1,10 @@
+
+[submodule "thirdparty/cub"]
+	path = thirdparty/cub
+	url = https://github.com/NVIDIA/cub.git
+[submodule "thirdparty/moderngpu"]
+	path = thirdparty/moderngpu
+	url = https://github.com/moderngpu/moderngpu.git
+[submodule "thirdparty/thrust"]
+	path = thirdparty/thrust
+	url = https://github.com/NVIDIA/thrust.git