detector extracts timestamps from human readable formats

[thorinaboenke]

Problem: #70
format_time() in detector.py assumed the Time is Unix timestamp, optionally with colon-separated suffix. It handled this by splitting on : and taking the first segment before casting to float: split(":")[0]
This breaks most other time formats containing a colon
12121.12:20 (testdata in test_core_detector.py) is not a valid timeformat at all
What generated this time log? Could this be some custom logging ( like processID.time) ?

Changes:

• 12121.12:20 not a valid timestamp, removed the :20 from the test data
• format_time() now uses the already existing _extract_timestamp() from TimeFormatHandler helper.
  --> this also now leads to if nothing is parsed, it returns silently 0 instead of error
• added a test file test_extract_timestamp.py
• added two more common formats to the TimeFormathandler

Note that probably not all possible timeformats are covered with this
Instead of hardcoded list, could consider dateutil (or similar), introduces python-dateutil dependency
int(dateutil_parser.parse(time).timestamp()) and might also not handle all possible formats correctly

[ipmach]

looks good!