[debug] [logging] Automatically turn off fs_debug_modeafter 24 hours + Refactor debugger and extract it to a separate class

* [debug] [logging] Automatically turn off fs_debug_mode after 24 hours, moved debug logic from Freemius to new FS_DebugManager class, fix a bug about logging attempt to DB when table does not exist.

* Removed useless $ON static variable, using $_isStorageLoggingOn

* Removed useless $ON static variable, using $_isStorageLoggingOn

* Removed useless `off` method and redundant checks

Author: DanieleAlessandra