[YCQL] LDAP integration for YCQL

[ajcaldera1]

Tracked by parent issue #2393. Ask is to support LDAP authentication in YCQL. We should follow the same type of parameters that YSQL uses for enabling LDAP authentication.

[ajcaldera1]

I've received some additional feedback on this item that we need to support search + bind as well as simple bind with LDAP in YCQL.