SecurityTokenExpiredException when the server runs for a few hours

[Tim-Pohlmann]

When the server runs for a while it stops handing out valid JWT tokens. They all have the same expiration date. The reason for this is the fact that JwtFactory is Singleton and injects IOptions. JwtIssuerOptions.IssuedAt is set to DateTime.UtcNow at program start and never reevaluated.