Added Etrade api.

[matias-favale]

Tested this locally successfully.

[BR-Nicholas-Prado]

Perhaps this worked at the time, but Etrade currently rejects this oauth attempt.

steps

1. used EtradeApiExample as the main class of a new project
2. changed the key and secret to match my sandbox key and secret
3. ran with gradle
4. pasted the authorize application url into a browser
5. provided my etrade credentials to that web page within 60 seconds

expected behavior

etrade page asks for me to consent to the application

observed behavior

etrade page complains that a login delay or other problem prevented authentication

I know that the test example class uses the sandbox api rather than the production api because the maven checkstyle complained when I tried to build a jar from the fork. I know that my credentials are correct because I use a password manager to log in to etrade and used the same. I know that the api key and secret are correct because I used etrade's example code to perform oauth with it and that showed their terms page.

For whatever reason, this pr does not correctly authenticate with etrade, at this time.