v0.5.0: OpenWeatherMap and plugin customisation

Version v0.5.0 of FlexMeasures is out (see changelog). Aside from great additions to the documentation (tutorials!) and some smaller things, there's new features for customisation of your project and an important switch to how you can retrieve weather forecasts!

OpenWeatherMap

FlexMeasures has a CLI command to retrieve weather forecasts from a third party. Very handy. We used DarkSky for this, but they got bought by Apple and will discontinue their open API in August 2021. So we switched to OpenWeatherMap. IIf you were using this feature, there is not much you have to do. Create an account there and set ``OPENWEATHERMAP_API_KEY`` in the FlexMeasures config.

This work was also done in Pull Request 113.

Plugin customisation

Plugins in FlexMeasures are crucial ― they allow a developer to create a customer-centric FlexMeasures solution. We at Seita are using them extensively now.

It's important that the developer can control look&feel. So this version of FlexMeasures allows to the URL routes and many smaller details in the UI.

This work was done in Pull Requests 106, 123 and 139.

Entity addressing

This one is a deeper technical issue behind the scenes, but crucial for a setting in which FlexMeasures talks to other parties about the same assets, or even multiple FlexMeasures instances do that.

Addressing entities (assets) in non-specific ways can lead to confusion and hard-to-detect data integration errors. We started a new entity addressing schema (`fm1`) which identifies any sensor (from assets, weather sensors, markets all the way to actuators we hope to add soon) with only their ID (see docs). This prepares for our new data model where this is commonplace (see our log of the previous version 0.4.0).

This work was also done in Pull Request 81.