Add 3D House Planner

[mathus1]

https://www.3dhouseplanner.com/

3D House Planner is the professional home design web application that allows you to design houses and apartments.

By submitting this pull request I confirm I've read and complied with the below requirements.

Failure to properly do so will just result in the pull request being closed and everyone's time wasted. Please read it twice. Most people miss many things.

• [x] I have read the Contribution guidelines and I am confident that my PR is suitable.
• [x] This pull request has a descriptive title. For example, Add [App name], not Update readme.md or Added new entries.
• [x] The app I added is not a duplicate.