[REF] Remove references to indico.web.wsgi.*

also remove some unused imports
[REF] remove the "if DEV: reload" crap
[REF] Get rid of MaKaC.common.general

It was utterly useless and just defined one constant with *very*
questional behavior (reload() calls in htdocs)
[DEL] Remvoe the old WSGI file
[FIX] Log exception reaching the WSGI layer
[DEL] Remove the legacy WSGI/mod_python layer