Add targets in Web project

This allow to copy binaries and make the project work.

Update example model in appsettings

LLama.Web/LLama.Web.csproj

@@ -1,5 +1,5 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
-
+  <Import Project="..\LLama\LLamaSharp.Runtime.targets" />
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
     <Nullable>disable</Nullable>

LLama.WebAPI/appsettings.json

@@ -6,5 +6,5 @@
     }
   },
   "AllowedHosts": "*",
-  "ModelPath": "..\\..\\LLamaModel\\ggml-model-f32-q4_0.bin"
+  "ModelPath": "..\\LLama.Unittest\\Models\\llama-2-7b-chat.Q4_0.gguf"
 }