ASTE version v3.0.0

Dear preCICE community,

We are happy to announce a new release of our artificial solver testing environment ASTE. It's been a while since the last release and a lot of things have changed. The main points are:

• ASTE has fully been ported to the VTK library and its format such that no custom data structures are used.
• The user-interface has now been unified as good as possible for the main cpp core (precice-aste-run) as well as the variety of python tools.
• We have created a dedicated ASTE documentation page on our website.
• We have created a dedicated ASTE tutorial in our tutorial repository (you can find toy example cases in the example directory as well).
• ASTE supports a so called replay-mode in order to emulate participants in a coupled simulation.
• ASTE supports new mapping variants implemented in preCICE: nearest-neighbor-gradient and linear-cell interpolation, which includes support for processing tetrahedra as well as gradient data.

With this major revision, we hope to improve the usability of ASTE a lot. If you have still suggestions on how to improve the user experience do not hesitate to let us know.

Most of the changes have been implemented by @kursatyurt , @boris-martin, @ariguiba and further preCICE team members (@davidscn and @fsimonis), thanks a lot.