Prepare for OpenDC 2.0 release (v1)

This pull request performs several preparations for the official release of OpenDC 2.0. 
This pull request mostly focuses on documentation changes.

## Details
1. Restructure project documentation
2. Migrate to Dokka 1.4.32
3. Merge CI builds into single workflow

1 files changed, 70 insertions, 0 deletions

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+# Toolchain Setup
+
+The OpenDC simulator is built using the [Kotlin](https://kotlinlang.org/) language. This is a JVM-based language that
+should appear familiar to programmers knowledgeable in Java or Scala. For a short interactive introduction to Kotlin,
+the [Learn Kotlin By Example](https://play.kotlinlang.org/byExample/overview) docs are a great place to start.
+
+For the build and dependency toolchain, we use [Gradle](https://gradle.org/). You will likely not need to change the
+Gradle build configurations of components, but you will use Gradle to execute builds and tests on the codebase.
+
+Follow the steps below to get it all set up!
+
+## Contents
+
+1. [Installing Java](#1-installing-java)
+1. [Building and Developing](#2-building-and-developing)  
+    1. [Setup with IntelliJ IDEA](#21-setup-with-intellij-idea)
+    1. [Setup with Command Line](#22-setup-with-command-line)
+
+## 1. Installing Java
+
+Kotlin requires a Java installation of version 8 or higher. Make sure to install
+the [JDK](https://www.oracle.com/technetwork/java/javase/downloads/index.html), not only the JRE (the JDK also includes
+a JRE).
+
+## 2. Building and Developing
+
+With Java installed, we're ready to set up the development environment on your machine. You can either use a visual IDE
+or work from a command line shell. We outline both approaches below, feel free to choose which you are most comfortable
+with. If in doubt which one to choose, we suggest going with the first one.
+
+## 2.1 Setup with IntelliJ IDEA
+
+We suggest using [IntelliJ IDEA](https://www.jetbrains.com/idea/) as development environment. Once you have installed
+any version of this IDE on your machine, choose "Get from Version Control" in the new project dialogue.
+Enter `https://github.com/atlarge-research/opendc` as URL and submit your credentials when asked.
+Open the project once it's ready fetching the codebase, and let it set up with the defaults (IntelliJ will recognize
+that this is a Gradle codebase).
+
+You will now be prompted in a dialogue to enable auto-import for Gradle, which we suggest you do. Wait for any progress
+bars in the lower bar to disappear and then look for the Gradle context menu on the right-hand side. In it, go
+to `opendc > Tasks > verification > test`. This will build the codebase and run checks to verify that tests
+pass. If you get a `BUILD SUCCESSFUL` message, you're ready to go to the [next section](architecture.md)!
+
+## 2.2 Setup with Command Line
+
+First, clone the repository with the following command:
+
+```shell script
+git clone https://github.com/atlarge-research/opendc
+```
+
+And enter the directory:
+
+```shell script
+cd opendc
+```
+
+If on Windows, run the batch file included in the root, as follows:
+
+```commandline
+gradlew.bat test
+```
+
+If on Linux/macOS, run the shell script included in the root, as follows:
+
+```shell script
+./gradlew test
+```
+
+If the build is successful, you are ready to go to the next section!