Custom thresholds

[tushartushar]

• Are we actually using 'ThresholdsParser'? I only see it is being used from tests!
• Also, we need to change the location of the threshold.txt and make sure that it is present in the target folder.
• Another thing is that if we don't find the file, we need to return the standard thresholds (and not throw an exception)

[Thodoras]

The functionality is implemented but I didn't add it in the main flow.
And yes adding it to the main flow someone would have to consider
to try to parse to and otherwise (maybe catch the exception?) use the default
attributes of the threshold class which is also already implemented.

I totally agree with the second bullet.