Cache access-token on database access ⚠️

[nikolaia]

Caching and management of the lifespan for the Azure.Core.AccessToken is considered the responsibility of the caller: each call should request a fresh token being requested.

Right now we request a new token on every connection:

chewbacca/src/Shared/AzureIdentity/AzureAdAuthenticationDbConnectionInterceptor.cs

Line 51 in 2d5a5ae

var token = await _credential.GetTokenAsync(tokenRequestContext, cancellationToken);

We are probably saved by connection-pooling but should reuse the token on the next connection opening if it's still valid.

PS: Remember to check if it's valid x seconds into future as there will be some delay from when we check the token expiration until the actual connection is made.