Add ability to set client name when using RedisConfiguration

[lorenh]

Describe the solution you'd like
Using a RedisConfiguration section in appsettings.json, (using individual configuration fields instead of a combined connection string) I'd like to be able to set the client name of the connection. (see name / ClientName row of this table https://stackexchange.github.io/StackExchange.Redis/Configuration#configuration-options) I don't currently see a way to do that.

Describe alternatives you've considered
One alternative might be to switch our configuration to use configuration strings and specify client name that way, although we haven't experimented with that yet.