Revert "homepage headline and the date of the next raceday can now be updated through the admin interface"

This reverts commit 5e772940e67c09fc8c94ca2c3198cda8f6c1fa29.
Revert "added a new table for misc variables so that simple site values can be edited through the CMS. current values include the homepage headline and upcoming raceday date"

This reverts commit b1b511fb3bb0575bcde5cad35eb8b30e7a9cb08f.