LDAP BaseDN improvements

[meister]

Disregard branch name, originally idea was a bit different..

Default behaviour is exactly the same as before, however --ldap-base-dn parameter now supports placeholder {username}. If the placeholder is found, the whole --ldap-base-dn is used as a DN.

Addresses issue https://github.com/shipyard/shipyard/issues/695

[ehazlett]

Since this can be anything perhaps it would be better as {baseDN} or something?

[meister]

The idea is that the placeholder is for the username variable that is used for authentication.
So for example: A user by the username martin logs in.

• When configured with --ldap-base-dn="cn=users,cn=accounts,dc=company" would produce LDAP dn cn=martin,cn=users,cn=accounts,dc=company
• When configured as --ldap-base-dn="uid={username},cn=users,cn=accounts,dc=company" would produce LDAP dn uid=martin,cn=users,cn=accounts,dc=company. {username} being the direct replacement from the login form (and variable used inside the method as well).

[ehazlett]

Hey sorry for the delay -- this needs a rebase. Thanks!

[meister]

Branch should be now up to date with master. Removed excess files that were added previously.

[ehazlett]

lgtm