Make the "2.0.x" branch the default branch

Problem/Motivation

Currently, "8.x-1.x" is still the projects default branch. This can easily bring confusion to developers working on this project, as it currently defaults to an old version of the module. Furthermore, any issue MRs created will default to the default branch, no matter the issue's target version.

Steps to reproduce

Proposed resolution

Make the "2.0.x" branch the default branch.

Remaining tasks

User interface changes

API changes

Data model changes