Adding yamllinter to ci steps (#1556)

* Adding yaml linter to ci check

* Minor linting fixes from yamllint

* Changing CI to install python pkgs from requirements.txt

- adding in a secondary requirements.txt for tests
- moving yamllint to tests requirements

.yamllint

@@ -0,0 +1,16 @@
+---
+extends: default
+
+rules:
+  braces:
+    min-spaces-inside: 0
+    max-spaces-inside: 1
+  brackets:
+    min-spaces-inside: 0
+    max-spaces-inside: 1
+  indentation:
+    spaces: 2
+    indent-sequences: consistent
+  line-length: disable
+  new-line-at-end-of-file: disable
+  truthy: disable