Feature: Keyword count over time periods

[bendavidsteel]

We'd like to be able to provide a list of keywords to a function in seldonite, and get back a count of the occurences of the keywords in title and texts in news articles both over all time, and over time periods, in a similar fashion to Google trends.

I've started a function to do this here:

seldonite/seldonite/analyze.py

Line 13 in e17feae

def keywords_over_time(self, keywords: List[str]):

Maybe add an extra keyword parameter that can take 'all', 'year' and 'month' for example