Web designer should run three versions long term

[davetcc]

Now that the designer is a docker image, we can easily host more than one version of it.

There should be three versions of webdesigner running on the server. Patch versions will not bump the versions, only major or minor updates.

• designer-next subdomain - the latest version available.
• designer subdomain - the stable version, basically version - 1.
• designer-prev - the previous version, basically version -2.

Let's take examples:

• Designer Next - 5.1.4
• Designer - 5.0.3
• Designer Prev - 4.5.11

[davetcc]

This will be backported into 4.5.10, making version 4.5.11. As well as the 5.0 release.