Core - Added node provider plugin feature type

Visual Scripting - Removed all nodes

src/Artemis.Core/Plugins/Nodes/NodeProvider.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Reflection;
+using SkiaSharp;
+
+namespace Artemis.Core.Nodes;
+
+/// <summary>
+///     Allows you to register one or more <see cref="INode" />s usable by node scripts.
+/// </summary>
+public abstract class NodeProvider : PluginFeature
+{
+    private readonly List<NodeData> _nodeDescriptors;
+
+    /// <summary>
+    /// Creates a new instance of the <see cref="NodeProvider"/> class.
+    /// </summary>
+    public NodeProvider()
+    {
+        _nodeDescriptors = new List<NodeData>();
+        NodeDescriptors = new ReadOnlyCollection<NodeData>(_nodeDescriptors);
+        Disabled += OnDisabled;
+    }
+
+    /// <summary>
+    ///     A read-only collection of all nodes added with <see cref="RegisterNodeType{T}" />
+    /// </summary>
+    public ReadOnlyCollection<NodeData> NodeDescriptors { get; set; }
+
+    /// <summary>
+    ///     Adds a node descriptor for a given node, so that it appears in the UI.
+    ///     <para>Note: You do not need to manually remove these on disable</para>
+    /// </summary>
+    /// <typeparam name="T">The type of the node you wish to register</typeparam>
+    protected void RegisterNodeType<T>() where T : INode
+    {
+        RegisterNodeType(typeof(T));
+    }
+    
+    /// <summary>
+    ///     Adds a node descriptor for a given node, so that it appears in the UI.
+    ///     <para>Note: You do not need to manually remove these on disable</para>
+    /// </summary>
+    /// <param name="nodeType">The type of the node you wish to register</param>
+    protected void RegisterNodeType(Type nodeType)
+    {
+        if (!IsEnabled)
+            throw new ArtemisPluginFeatureException(this, "Can only add a node descriptor when the plugin is enabled");
+        if (nodeType == null)
+            throw new ArgumentNullException(nameof(nodeType));
+        if (!nodeType.IsAssignableTo(typeof(INode))) 
+            throw new ArgumentException("Node has to be a base type of the Node-Type.", nameof(nodeType));
+
+        NodeAttribute? nodeAttribute = nodeType.GetCustomAttribute<NodeAttribute>();
+        string name = nodeAttribute?.Name ?? nodeType.Name;
+        string description = nodeAttribute?.Description ?? string.Empty;
+        string category = nodeAttribute?.Category ?? string.Empty;
+        string helpUrl = nodeAttribute?.HelpUrl ?? string.Empty;
+        
+        NodeData nodeData = new(this, nodeType, name, description, category, helpUrl, nodeAttribute?.InputType, nodeAttribute?.OutputType);
+        _nodeDescriptors.Add(nodeData);
+        NodeTypeStore.Add(nodeData);
+    }
+    
+    protected TypeColorRegistration RegisterTypeColor<T>(SKColor color)
+    {
+        return NodeTypeStore.AddColor(typeof(T), color, this);
+    }
+    
+    private void OnDisabled(object? sender, EventArgs e)
+    {
+        // The store will clean up the registrations by itself, the plugin feature just needs to clear its own list
+        _nodeDescriptors.Clear();
+    }
+}