Nodoc: Config File

**Issue Label:**
* [ ] Bug
* [ ] New feature
* [x] Enhancement

**Description:**

I'm new to this cryptowatch script, and I have no clue on how to actually create that portfolio file, what format it should be in. IMO a little bit of documentation would add a ton of traction to this script.

I tried to edit the configuration, but it's little to no use: having to supply one address per crypto is pointless as most people will have several receive addresses, and also I don't see how to add cryptos (Stratis, Peercoin, Dogecoin, IOTA, ADA all seem to be good candidates). A small doc about how to add an API endpoint allowing to monitor this or that would be great.