Add workflow, link checker and modify Readme (#30)

* Add test workflow for dockerfile build
* Add link checker workflow
* Modify Readme to divide input for build strategies

Signed-off-by: divyansh42 <diagrawa@redhat.com>

.github/workflows/link_check.yml

@@ -0,0 +1,18 @@
+name: Link checker
+on:
+  push:
+    paths:
+      - '**.md'
+  pull_request:
+    paths:
+      -'**.md'
+
+jobs:
+  markdown-link-check:
+    name: Check links in markdown
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - uses: gaurav-nelson/github-action-markdown-link-check@v1
+        with:
+          use-verbose-mode: true