Refine .gitignore to include additional directories and files for client and server, enhancing project structure and clarity.

Server/config/spark/config.json

@@ -0,0 +1,4 @@
+{
+  "_header": "spark configuration file - https://spark.lucko.me/docs/Configuration",
+  "backgroundProfiler": true
+}

Server/config/spark/tmp-client/about.txt

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+# What is this directory?
+
+* In order to perform certain functions, spark sometimes needs to write temporary data to the disk. 
+* Previously, a temporary directory provided by the operating system was used for this purpose. 
+* However, this proved to be unreliable in some circumstances, so spark now stores temporary data here instead!
+
+spark will automatically cleanup the contents of this directory. 
+(but if for some reason it doesn't, if the server is stopped, you can freely delete any files ending in .tmp)
+
+tl;dr: spark uses this folder to store some temporary data.