Authenticate to LDAP using keytab

[joernheissler]

Hello,

currently I need to specify binddn and bindpass in POST /auth/kerberos/config/ldap.
Could you please add the option to authenticate using the kerberos keytab I already provided in /auth/kerberos/config?

I don't know "go" and all the libraries, but I think that most required code already exists. Maybe go-ldap needs another constructor besides NewClientWithKeytab that takes a keytab blob instead of a filename?

The shell equivalent that works for me is:

kinit -k -t vault-stg.keytab 'vault-stg$'
ldapsearch -H ldaps://ldap1.example.net/ -Y GSSAPI -b DC=example,DC=net -O maxssf=256 '(query)'