Insecure entropy in Argo CD's PKCE/Oauth2/OIDC params

Impact

All versions of Argo CD starting with v0.11.0 is vulnerable to a variety of attacks when an SSO login is initiated from the Argo CD CLI or UI. The vulnerabilities are due to the use of insufficiently random values in parameters in Oauth2/OIDC login flows. In each case, using a relatively-predictable (time-based) seed in a non-cryptographically-secure pseudo-random number generator made the parameter less random than required by the relevant spec or by general best practices.