Merged PR 636: Release 4.0.0

# PrimAITE 4.0.0 Release Note

## 📰 Headlines 📰

* **Major Release** - This is the first major release of PrimAITE that has been published since PrimAITE 2.0.0. Users are encouraged to also familiarise themselves with [what's new in PrimAITE 3.0.0](todo: 3.0 release note link).
* **Plugins** - PrimAITE now supports external plugins to extend existing functionality, such as new node types, services, applications, agent types, observations, actions, and rewards.
* **Improved config schema** - The YAML config files have a new schema which simplifies the definition of agents by using named references in actions and observations instead of id references.
* **Use Case 7** - Introduction of much larger UC7 network with example notebooks and config files.

## ✨ What's new ✨

- **Use Case 7** is a new pre-defined scenario in PrimAITE with a more complex set of nodes that demonstrates some of the new capabilities of PrimAITE 4.
- **Threat Actor Profiles** are a new type of malicious scripted agent:
  - Extensible base class that allows defining a multi-stage kill chain with success conditions and network knowledge tracking.
  - TAP001 agent - agent that exfiltrates and corrupts data from a database.
  - TAP003 agent - agent that maliciously introduces ACL rules to a network to disrupt normal users.
- **Users, Terminals, SSH, and Command&Control** were [introduced in PrimAITE 3.3]().
- **Determinism** Support for determinism by setting and logging randomness seeds.
- **Action Masking** (introduced in 3.2.0).
- **MARL support** (introduced in 3.0.0).
- **Logging** was improved by adding the following:
  - detailed information about agent actions, decisions, and rewards.
  - the full state of the simulation after each environment step.
  - sys logs for each node.
  - pcap logs for each network interface.
- **Domain Randomisation** - the Gym environment can use different variations of the same scenario, alternating between them each episode by providing a folder of YAML files instead of a single file at initialisation.

## 👍 General Improvements 👍
- The organisation of the codebase has been improved by splitting long files into smaller ones.
- Agent logs can now show observation history and more detail about the reward.
- Some classes' `.show()` methods now show more useful or correct information (like agents, and networks).
- More example notebooks and introduction of how-to guides in the Sphinx docs.
- Ability to set scenario-wide default values for certain actions like scan, node power-off, node start-up, etc.
- It's now easier to build complex networks with the new, extensible `NetworkNodeAdder` class.
- NMAP application.
- The YAML config files:
  - support extended classes from plugins
  - information has been deduplicated - actions no longer rely on IDs, instead users can specify meaningful labels.
  - more objects have default values so there is less boilerplate.
  - the way agent settings are defined has been standardised.
  - more data va...

src/primaite/VERSION

@@ -1 +1 @@
-4.0.0-dev
+4.0.0