Move Gradle wrapper and precommit checks into OpenSearch repo. (opensearch-project#1664)

* Move Gradle checks into OpenSearch repo.

Signed-off-by: dblock <dblock@amazon.com>

* Use working-directory for gradle wrapper validation.

Signed-off-by: dblock <dblock@amazon.com>

* Use https://github.com/gradle/wrapper-validation-action.

Signed-off-by: dblock <dblock@amazon.com>

Author: dblock

.github/workflows/precommit.yml

@@ -0,0 +1,16 @@
+name: Gradle Precommit
+on: [pull_request]
+
+jobs:
+  precommit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          java-version: 11
+          distribution: adopt
+      - name: Run Gradle
+        run: |
+          ./gradlew precommit --parallel

.github/workflows/wrapper.yml

@@ -0,0 +1,10 @@
+name: Validate Gradle Wrapper
+on: [push, pull_request]
+
+jobs:
+  validate:
+    name: Validate
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: gradle/wrapper-validation-action@v1