Add field variable to normalize function in eventlog.py

[mmantyla]

Now normalization is always fixed to column "m_message". Ideally user should be give the field to what the normalization is based on. This would allow multiple normalization calls.

Also change name from normalize to masking.

LogLead/loglead/enhancers/eventlog.py

Line 365 in fa0f56f

def normalize(self, regexs=masking_patterns_drain, to_lower=False, twice=True):