fix: add missing explicit property declarations to avoid deprecated dynamic property errors

[amulet1]

Add missing explicit property declarations to avoid deprecated dynamic property errors:

• Declare $_request, $_driver, $_state, $_policykey
• Fix typo: Horde_Controller_Reqeust_Http -> Horde_Controller_Request_Http

This is a simple fix, but maybe we should also refactor a little bit?

It looks like this class is not extended, and only used in one place. Maybe it makes sense to:

• use constructor property promotion,
• drop _ from variable names and add explicit types where is it absolutely clear.

Or we can do it later.

[amulet1]

Also:

• add missing classes accidentally omitted in prior fixes
• add return type declaration to getIterator()

A new alpha release is requested.