re-enable slides text keyword extraction

[rngadam]

see:

https://github.com/coderbunker/gas/blob/master/src/profiles/convert.js#L47

commented out because I had not paid / put a credit card on the Google Cloud services.

application:

• can create word cloud of most frequent competencies from keywords
• keyword exported to .json would be searchable in the profile slides search function.

[andiechu]

I've already created a issue for this: #44