Write installation steps in readme.md

[fume]

While waiting for the deployment automation (#6), we should write the installation steps in the readme:

• How to deploy the custom policies in AAD B2C
• How to deploy and configure the SPIDProxy
• How to get started with the demo.spid.gov.it environment

[asorcinelli]

Hi, I would like to try your solution. Is it still current? Does the installation documentation not yet exist?

[fume]

Hi @asorcinelli , the solution is still current and widely used. Official docs is still not yet available but you can use the one available in #44

[asorcinelli]

Hi @fume, thanks for the reply. Yes, I saw the documentation and managed to set up the entire environment. I have a problem, but I don't want to dwell on it here as I don't think it's the right place. Could I contact you somehow and explain the problem? Maybe you can help me. Thank you.