[task] Update Quickstart Guide to use the OpenMMO>Quick Build Menu

[francy51]

Text Mesh Pro Install

• Remove Steps 2 and 3 (TMP Extras are not needed for the quickstart, they do not belong here).
  -Give this section an appropriate header: "Importing TextMeshPro Essentials" etc

Basic Installation
-Step 4 can be removed - The Quick Build (and Change Build) menu automatically changes to the correct .NET version.

• Steps 8, 9, 10 and 11 can be removed (Those belong in the Full Manual, they only confuse users in the quickstart)
  -Replace Steps 8, 9, 10 and 11 with:

8. Access the "OpenMMO>Change Build" Menu at the top of the Unity Editor and select "Host and Play"
9. Press Play in the Unity Editor to launch OpenMMO in test mode.

How To Switch Builds
-Remove this section and replace it with the following:
Building The Client and Server

OpenMMO does not support Zones and other core features inside the editor because of technical limitations. You must build your project to utilize the full functionality of OpenMMO.

1. First verify that you have the Login Scene open in the Unity Editor (Other scenes will build, but they will fail when you launch the executable)
2. To build OpenMMO - Access the "OpenMMO>Quick Build" Menu and choose the operating system you would like to target. Select the "Client and Server" option.
3. The build will take a minute...just wait until the [BUILD REPORT] appears in the Unity Console before continuing. (You can see details about the build by clicking the Build Report)
4. Navigate to your Project Folder and locate the _BUILD folder. Inside that folder you will find Client and Server folders. Open the Server folder and launch server.exe
5. The server application should launch multiple windows when it launches. If that did not happen you may have missed a step in the Basic Installation instructions.
6. Once the server is up and running, head back to your _BUILD folder and launch the client application.
7. Register an Account and Login.