Stop pushing Ansible based Insights Image and remove outdated code from configuration repo

[aht007]

As we have moved to Native Docker image for our Insights Service and it has been working fine for quite time, we feel confident now that we can stop the image building process for our old Ansible based Image and remove all the code related to it from configuration repo.
A/Cs:

• Coordinate with SRE and stop pushing the old image.
• Remove the code related to building the Ansible based Insights Image
• Remove the -dev suffix used in edx-analytics-dashboard image building and image push workflows.
• Also make a devstack PR for removing the -dev suffix from Insights Image and use the new image.