Auto SSL Certificate + Domain Binding on Azure

Insights.US is looking for a developer for a specific code to be integrated into our app.

The problem:
(1) We have various clients with various domains. Our SaaS solution needs to be integrated into their subdomains (sub.clientdomain.com). We need these domains to get SSL certificates that will be automatically configured on our Azure servers (IIS binding / webapp) and renewed every year.
(2) We have an old VM with a fixed IP. We need to develop a cost effective solution on Azure to redirect all requests to this IP to our central IP, which directs to webapps.

The solution we need to develop:
1. Client defines DNS records (A records or CNAME) to our servers.
2. Our servers automatically issue an SSL certificate using LetsEncrypt, and manage the configuration.
3. We apply the same solution to a few dozens existing sub domains, with existing a records to our servers.
4. We renew all these certificates every 6 or 12 months automatically.
5. We move sites from the old domain into the new one.