Alias isMaster in mongocryptd and attach appropriate response field

We will apply the same aliasing functionality used for the mongod and mongos isMaster commands in SERVER-49986 to CrytpDCmdIsMaster in the enterprise repository. They implement isMaster for mongocryptd.

mongocryptd is the client side FLE (field level encryption) support daemon, which drivers talk to.

Similarly to the mongod and mongos isMaster commands, we will decide to return an “isWritablePrimary” response field instead of an “ismaster” response field if we’re running the “hello” command.