OPENDJ-2383 REST interface: Implement password modify action

Server-side implementation. See the equivalent change in the SDK.

LdapHttpApplication.java, CollectClientConnectionsFilter.java::
In LdapHttpApplication ctor, do not use the SecurityContextFactory (alas, this duplicates code :( ),
instead create the SecurityContext in CollectClientConnectionsFilter.doChain().

SdkConnectionAdapter.java:
In extendedRequestAsync(), set the authorization entry from the authentication info.

Converters.java:
In newSDKResult(), return a PasswordModifyExtendedResult for a PasswordModifyExtendedOperation.