Merged PR 450: Terminal Service Class

## Summary
This PR is the base implementation of the Terminal Service Class, containing the skeleton structure for #2711.

## Test process
Future me's problem - see #2714

## Checklist
- [X] PR is linked to a **work item**
- [X] **acceptance criteria** of linked ticket are met
- [X] performed **self-review** of the code
- [ ] written **tests** for any new functionality added with this PR
- [] updated the **documentation** if this PR changes or adds functionality
- [ ] written/updated **design docs** if this PR implements new functionality
- [X] updated the **change log**
- [X] ran **pre-commit** checks for code style
- [ ] attended to any **TO-DOs** left in the code

Related work items: #2711

docs/source/simulation_components/system/services/terminal.rst

@@ -0,0 +1,56 @@
+.. only:: comment
+
+    © Crown-owned copyright 2024, Defence Science and Technology Laboratory UK
+
+.. _Terminal:
+
+Terminal
+########
+
+The ``Terminal`` provides a generic terminal simulation, by extending the base Service class
+
+Key capabilities
+================
+
+ - Authenticates User connection by maintaining an active User account.
+ - Ensures packets are matched to an existing session
+ - Simulates common Terminal commands
+ - Leverages the Service base class for install/uninstall, status tracking etc.
+
+
+Usage
+=====
+
+ - Install on a node via the ``SoftwareManager`` to start the Terminal
+ - Terminal Clients connect, execute commands and disconnect.
+ - Service runs on SSH port 22 by default.
+
+Implementation
+==============
+
+- Manages SSH commands
+- Ensures User login before sending commands
+- Processes SSH commands
+- Returns results in a  *<TBD>* format.
+
+
+Python
+""""""
+
+.. code-block:: python
+
+    from ipaddress import IPv4Address
+
+    from primaite.simulator.network.hardware.nodes.host.computer import Computer
+    from primaite.simulator.system.services.terminal.terminal import Terminal
+    from primaite.simulator.network.hardware.node_operating_state import NodeOperatingState
+
+    client = Computer(
+        hostname="client",
+        ip_address="192.168.10.21",
+        subnet_mask="255.255.255.0",
+        default_gateway="192.168.10.1",
+        operating_state=NodeOperatingState.ON,
+    )
+
+    terminal: Terminal = client.software_manager.software.get("Terminal")