setup: clean up macOS setup script

- Spaces -> tabs.
- Remove "brew install python" because it's already a dependency of the
  px4-dev tap.
- Remove "brew install ccache" as we can also add it to the px4-dev tap.
- Don't try to update pip installation, it works fine as is.
- Install pip dependencies as user, no need for system-wide install.

Tools/setup/OSX.sh

@@ -29,28 +29,20 @@ if [[ $REINSTALL_FORMULAS == "--reinstall" ]]; then
 	brew doctor
 
 	brew tap PX4/px4
-  brew reinstall px4-dev ccache
+	brew reinstall px4-dev
-
-  # python dependencies
-  brew install python3
-  sudo -H python3 -m pip install --upgrade pip
 else
 	if brew ls --versions px4-dev > /dev/null; then
 		echo "px4-dev already installed"
 	else
 		echo "Installing PX4 general dependencies (homebrew px4-dev)"
 		brew tap PX4/px4
-    brew install px4-dev ccache
+		brew install px4-dev
-
-    # python dependencies
-    brew install python3
-    sudo -H python3 -m pip install --upgrade pip
 	fi
 fi
 
-# Python3 dependencies
+# Python dependencies
 echo "Installing PX4 Python3 dependencies"
-sudo -H python3 -m pip install -r ${DIR}/requirements.txt
+pip3 install --user -r ${DIR}/requirements.txt
 
 # Optional, but recommended additional simulation tools:
 if [[ $INSTALL_SIM == "--sim-tools" ]]; then