Create a simple admin interface

[0xRampey]

After the adminstrator logs in, he should be provided with basic functionality like Hard rescan and Music metadata. I suggest relocating those functions from the client player to this admin page.
Songs can be uploaded by the DC admins through an online/offline FTP client. No need to include that functionality here.

[0xRampey]

@SebastinSanty If you're doing this, can you send in the commit for relocating the functions first? I want to offload all the potential client functions that can change the database so that we can proceed to a production-ready alpha version.