Allow configuring tls cert filepath

[nicksherron]

This change allows setting tls cert and private key as well as ca authority file paths for configuring tls options for redis connection. Tests have also been added to test connecting to redis without tls and with using regeneratable custom tls keys

Flag	Env	Description	Default
redis-ca-cert	REDIS_CA_CERT	path to CA certificate file used when connecting to redis server	""
redis-client-cert	REDIS_CLIENT_CERT	path to client certificate file used when connecting to redis server	""
redis-client-key	REDIS_CLIENT_KEY	path to client key file used when connecting to redis server	""