grey out normalized functions

[jfilak]

Several functions on the top of FAF backtraces are usually normalized and it means that those functions are not significant and not relevant to the crash.

[mbrysa]

Currently the normalization "database" is stored in satyr: https://github.com/abrt/satyr/blob/master/lib/normalize.c
Satyr's Python API allows for normalization of whole stacktraces, so the only way to do this would be to diff the stacktrace before and after normalization, which seems inefficient. Definitely should be done offline and saved in the DB, possibly in the create-problems action as it loads and normalizes the stacktraces anyway.