Add metadata for source data

[jikaczmarski]

• [x] Net generation data
• [x] Capacity data
• [x] Consumption data
• [x] Price data

[eldobbins]

There is a validator for frictionless data packages at https://create.frictionlessdata.io. I uploaded metadata.json to it and it barfed at the license. Am going to try and fix it.

[eldobbins]

My change to the license section passed the frictionless test. I approve of this format!

I referenced this in the other issue and proposed a new structure for data/. If you like the new structure, can you shuffle the data into it and change the path to include a subdirectory. I intend this file to be the one that links all the different sections, though finishing capacity first is appropriate. We can make separate issues for the different sections.

[jikaczmarski]

I like it! We will want @ianalexmac to store his relevant CSVs here and add his metadata as well so I'll leave this open and rename accordingly.