minimalqmake on macOS with per-project installation does not work.

Nobody has claimed this yet.

Hi
It is observed that it is no more possible to get minimalqmake example included in fluid
distribution working on MacOS.

Steps to replicate.

(1) create a fresh new folder FluidTest and enter it.
(2) clone fluid from github and enter the ```examples/perproject/minimalqmake``` directory
(2) again clone fluid from GitHub in this directory so that ```fluid``` and ```src``` are siblings.
(3) open minimalqmake.pro in QtCreator on MacOS
(4) build main project minimalqmake (it will be successful)
(5) now run the application

The Expected behaviour is that the application should run.

However Current Behavior is that the application does not run
and it gives following error in QtCreator as:

```
10:00:31: Starting /Users/rmallah/FluidTest/fluid/examples/perproject/build-minimalqmake-Desktop_Qt_5_13_1_clang_64bit-Debug/src/src.app/Contents/MacOS/src ...
QML debugging is enabled. Only use this in a safe environment.
QQmlApplicationEngine failed to load component
qrc:/main.qml:5 module "Fluid.Controls" is not installed
```

Context:
I am trying to build the iOS version of an app that works in android.
getting it running in MacOS is important because it is a quick way
of reviewing the UI that is finally meant for iOS. Hence getting the
example working in MacOS is important .

Environment:
* Qt Version used: 5.13.1 Qt Creator Version: 4.10.0
* Operating system and version: MacOS Catalina 10.15.2
* Device: mac laptop

I understand that many variants of this problem has already been reported
and some are in closed state. But it looks like the thing does not really work
and i personally feel developer comfort is the key to engagement of more
developers that can contribute to this fine project which makes developing
app in Qt pleasant experience.

Regds
Rajesh Kumar Mallah.

Start with examples/perproject/minimalqmake/minimalqmake.pro and reproduce the macOS build and launch steps in QtCreator. Investigate why the built application cannot find the Fluid.Controls module; done means the minimalqmake application launches and loads main.qml without that error.

Written by the indexing model from the issue text.