* Undeclared variables shall not be used with oomph since they are
  demanded every time eclipse is started.
* Instead, use the "key" variable directly to demand the API key during
  the initial setup steps.
* The "PASSWORD" cannot be used since mylyn requires the API key in
  clear text and stores it as such. Thus, we are doomed to use the
  "STRING" variable type.

Issue-Ref: 3406
Signed-off-by: Alexander Diewald <diewald@fortiss.org>