Add a few infos to the docs

[helgoboss]

• Hardware controller buttons should always be set up in momentary mode, otherwise ReaLearn can't properly control the button's function.
• Before installing the new ReaLearn via ReaPack, uninstall the old ReaLearn
• Hint regarding conditional activation via programs https://forum.cockos.com/showpost.php?p=2340805&postcount=480
• Alternative to conditional activation as mentioned here: https://forum.cockos.com/showpost.php?p=2340750&postcount=478
• Mention hint Your controller has multiple modes and currently is in the wrong one. also in "Troubleshooting" section because it affects control direction as well
• Mention that rotary encoders should be put into relative mode to take full advantage of ReaLearn's capabilities.
• Mention that it only works in native mode, not in bridged mode