added installation instructions

extensions/whisper_stt/README.md

@@ -0,0 +1,39 @@
+# Installation instructions
+
+- On all platforms, run `pip install -r requirements.txt` in this folder
+- You need **PortAudio** to run the speech recognition. Below are guides for all platforms
+
+
+## Windows
+
+- You don't need to do anything, `pyaudio` already comes with PortAudio included on Windows.
+
+## Mac
+
+```commandline
+brew install portaudio
+brew link --overwrite portaudio
+pip install pyaudio
+```
+
+## Linux
+
+- You have to use your distro's package manager to install PortAudio.
+
+### Ubuntu / Debian / Mint
+
+```commandline
+sudo apt install portaudio19-dev python3-pyaudio
+```
+
+### Arch / Manjaro
+
+```commandline
+sudo pacman -S portaudio
+```
+
+### Fedora
+
+```commandline
+sudo dnf -y install portaudio
+```