feat: add gh action to build Chatwoot CE/foss docker image (#4406)

Github action to build and push chatwoot-ce(foss) edition images. This action will run on merges to master, develop and when tags are created. Corresponding docker tags are as follows.

GitHub branch/tag  -->	docker tag
----
master 	--> latest-ce
develop 	---> develop-ce
v2.3.2 	---> v2.3.2-ce
v* 	---> v*-ce

Fixes #4388

.github/workflows/publish_foss_docker.yml

@@ -0,0 +1,55 @@
+# #
+# # This action will publish Chatwoot CE docker image.
+# # This is set to run against merges to develop, master
+# # when tags are created.
+# #
+
+name: Publish Chatwoot CE docker images
+on:
+  push:
+    branches:
+      - develop
+      - master
+    tags:
+      - v*
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+      GIT_REF: ${{ github.head_ref || github.ref_name }} # ref_name to get tags/branches
+    steps:
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Strip enterprise code
+        run: |
+          rm -rf enterprise
+          rm -rf spec/enterprise
+
+      - name: set docker tag
+        run: |
+          echo "DOCKER_TAG=chatwoot/chatwoot:$GIT_REF-ce" >> $GITHUB_ENV
+
+      - name: replace docker tag if master
+        if: github.ref_name == 'master'
+        run: |
+          echo "DOCKER_TAG=chatwoot/chatwoot:latest-ce" >> $GITHUB_ENV
+
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v2
+        with:
+          file: docker/Dockerfile
+          push: true
+          tags: ${{ env.DOCKER_TAG }}