Adapt database connection creator

[gplssm]

This branch provides OEDB connection establishment via ego.io own config file. If this config file does not exist, it should be interactively be created (the computer will ask you ;-) ).

This new functionality relies of methods available in "features/own-config-file" of ego.io. Please use this branch to test this PR. Once, the PR is merged we need a new ego.io Release. I suggest to make a 0.2.1 release

For the reviewers, please check if the data_processing script still runs and everything works like normal/expected.

[lukasol]

Since I never run the dp I cannot really test and thus review this PR. I think @ulfmueller and @Ludee are the ones that could do so.

[gplssm]

@lukasol I think review by @ulfmueller and @Ludee is sufficient. Thx.

[Ludee]

Start testing now:
ego.io branch = features/own-config-file
data_processing branch = fix/#18

[Ludee]

creation of .egoio/config.ini works.
The use of the file didn't work for me. I get asked for connection details again.

[Ludee]

Problem was that oemof.db has to be installed in the newest version (v0.0.5)

[Ludee]

It is complicated (three repos) with a lot of potential errors. But it works as desired.
A future job is to combine everything in oemof.db

[Ludee]

Is this still part of MS Release v0.3 or do we move it to v0.3.1? @gplssm

[gplssm]

We move it because it requires work to be done in ego.powerflow

[nesnoj]

The db access stuff is finished in openego/ego.io#34 and is ready for use. This PR might needs to be adapted..

[IlkaCu]

This PR is pretty old and still open. @gplssm: Is it still relevant?

[gplssm]

To be honest, I suggest to re-start from scratch! Changes included in this PR are pretty small and not to innovative. Furthermore, these are quite outdated...
If we still have the plan to align DB connection provider with other packages in the openego context, I suggest to use ego.io's connection provide as it's used in Ding0/eDisGo.

[ulfmueller]

I agree with @gplssm since in the meantime we created our own db connector in ego.io now without dependencies to oemof, we can use it like in the other apps (eTraGo, eDisGo and so on). Close this PR and create an issue?