v5.0.0: The "let's get organized" update

Facade was written using Python for the backend, and PHP for the
frontend. The frontend decision as purely about geting up and running
quickly and easily. However, I really never intended for it to be
permanent, or even necessary, to use the frontend as shipped. As such,
there has always been a separation of duties between the code which does
the actual work (facade-worker.py) and the code which feeds
configs/displays results (the PHP stuff). It is entirely possible to
replace the frontend with anything, so long as the proper data is fed
into the database.

This release consolidates the web frontend into its own subdirectory,
to make this distinction even more clear. It is a change that will
require manual intervention by a user. Basically, you need to edit your
/etc/apache2/apache2.conf file and add 'web/' to the end of the
Directory declaration, like this:
<Directory /path/to/facade/> -> <Directory /path/to/facade/web/>

Also your sites configuration file (probably
/etc/apache2/sites-available/facade.conf) like this:
DocumentRoot /path/to/facade/ -> DocumentRoot /path/to/facade/web/

This change is the result of some discussions as OSLS 2018 about using
Facade as the backend source for data with an alternate frontend.

This release also includes:

• Caching of data by week, which augments the monthly and annual views
• Minor improvements to the way filenames are handled internally, but
  this is a transparent change.

There is currently no support to view weekly data in the web UI, but
it's there in the database if you want to pull it directly.

Don't forget to run facade-worker.py after you update so that any pending
database updates can be properly processed.