Store quotes local

[muhme]

Retrieving and storing quotes, authors and categories locally. This cost less than 2 MB database size and has the following advantages:

• Faster delivery (especially if you are on the other side of the world, like in Japan)
• Be sure, everything is working if the zitat-service.de API is down or even no more existing
• No problems with privacy in contacting another server

Functionality:

• Initial database fill
• Admin button to update the database

Store only relevant tables and columns, e.g. no user or comments.

Open Questions:

• How to inform the joomla sites e.g. if a quote is deleted on zitat-service server e.g. for legal reason and should be removed from Joomla database too? Is there something like daily update service existing?