Minimize number of db queries in enodebd update cbsd

[jkmar]

Currently we have following queries
SELECT * FROM CBSDS FOR UPDATE;
UPDATE CBSDS;
SELECT * FROM CBSDS;
SELECT * FROM GRANTS;
we want the following:
SELECT * FROM CBSDS JOIN GRANTS; // without for update
UPDATE CBSDS;

Implement the following interface:

type EnodebdManager interface {
	FetchCbsd(runner sq.BaseRunner, serial string) (*DetailedCbsd, error)
	UpdateCbsd(runner sq.BaseRunner, cbsd *DBCbsd) error
}