[BUG] OEDB error

[birgits]

At the moment all functions where data is retrieved from the oedb are failing due to an issue with the oedialect. There are two issues.

The first is, that the URL changed to openenergyplatform.org, which needs to be adapted in ego.io. As in the long term we want to remove ego.io and only use saio, we could also change the functions to not use ego.io.

The second lies somewhere in the oedialect, though it is not yet clear where exactly. The error message is as follows:
ConnectionException: HTTP 405 (Method Not Allowed)

People from the oedb are working on this. Until it is fixed, all tests of functions retrieving data from the oedb are scipped (see PR #404). This issue serves as a reminder to remove the scipping of the tests, once the oedb issue is fixed.