Move Event Vocabularies to the place where they belong to.

``plone.app.event`` defines some **common vocabularies** about **weekdays** and **timezones**. Those where moved to ``plone.app.vocabularies`` since they are of general interest. 

Also we completed the vocabularies with all weekdays in its 3 forms (full, 3 letter, 2 letter) and all months in 2 form (full, 3 letter). All strings are translated already in ``plonelocales``.

The timezone-vocabularies are having an dependency on ``pytz`` (theres no other always-recent Olsen-DB timezone providing lib around). 

There are all timezones, only the common timezones and the available timezones. 
Latter need ``plone.app.event`` installed for Plone 4.3. 

In Plone 5 ``plone.app.event`` is available by default, but not used, because the plan is there to use the values from the controlpanel. This move was done in  ``plone.app.controlpanel`` ``timezone-controlpanel`` branch https://github.com/plone/plone.app.controlpanel/tree/timezone-controlpanel together with the changes. in ``plone.app.event`` 2.0.

Even w/o the merge of this ``plone.app.controlpanel`` and ``plone.app.event`` this branch of ``plone.app.vocabularies`` is 100% functional.