info missing on custom-ux-sample

> Please provide us with the following information:
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### This issue is for a: (mark with an `x`)
```
- [ ] bug report -> please search issues before submitting
- [ ] feature request
- [y] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
>clone repo and fill in the config.aad and bingmaps key, where to find the rest of the values is missing

### Any log messages given by the failure
> application fails to load

### Expected/desired behavior
>

### OS and Version?
> Windows 10

### Versions
>latest pull

### Mention any other details that might be useful
require info on where to get values for ###{APP_BUILDER_API_URL}### , ###{DISPLAY_RELEASE_VERSION}### and ###{REACT_APP_WEATHER_API_URL}### at https://github.com/Azure-Samples/blockchain-devkit/blob/master/connect/web/workbench/custom-ux-sample/src/common/config.js
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