MSAL.Net Cache is backward and forward compatible

[kpanwar]

Why?
To enable an easy migration of applications using ADAL.Net to MSAL.Net, we'd want the cache to be backward and forward compatible in both libraries.

What?
MSAL.Net should be able to:

• read ADAL.NET v3.0 cache blobs and migrate refresh tokens to MSAL cache format.
• write both ADAL.NET v3.0 blob format and MSAL.NET Json format.
• Add a test where HasStateChanged is false due to the token not in the cache, thus not deleted, thus no state changed (See Add a test where HasStateChanged is false  #252)
• RequestParams should not be passed in the token cache. request classes must pass exact information to the methods (RequestParams should not be passed in the token cache methods #317)

[jmprieur]

Done.
See https://aka.ms/msal-net-2-released