storage/mariadb: use a different method of storing request user information

[Wessie]

We currently store a single entry for each IP/Host in the requesttime table in the database, instead we could store multiple entries in a new requests table, that also tracks what song was requested.

This should give us more data about what songs our users want and how often people request

[Wessie]

As found out earlier, the ip column currently does not have a UNIQUE constraint on it, so we can actually implement this without a schema change. The only potential problem would be the site code assuming the same thing we did before, that only one row exists of any singular ip

[Wessie]

https://github.com/R-a-dio/site/blob/4d90156ce7834d882fe0b9664b262474402e5139/app/start/global.php#L239

[Wessie]

The current schema also does not contain an index on the time column, so selects with an order by use a filesort over the full contents of the table