Exercise multiple ansible versions in CI (#8172)

* Ansible: separate requirements files for supported ansible versions

* Ansible: allow using ansible 2.11

* CI: Exercise Ansible 2.9 and Ansible 2.11 in a basic AIO CI job

* CI: Allow running a reset test outside of idempotency tests and running it in stage1

* CI: move ubuntu18-calico-aio job to stage2 and relay only on ubuntu20 with the variously supported ansible versions for stage1

* CI: add capability to install collections or roles from ansible-galaxy to mitigate missing behavior in older ansible versions

requirements.txt

@@ -1,10 +0,0 @@
-ansible==3.4.0
-ansible-base==2.10.11
-cryptography==2.8
-jinja2==2.11.3
-netaddr==0.7.19
-pbr==5.4.4
-jmespath==0.9.5
-ruamel.yaml==0.16.10
-ruamel.yaml.clib==0.2.4
-MarkupSafe==1.1.1

requirements.txt

@@ -0,0 +1 @@
+requirements-2.10.txt