I only use the config files in /etc/openhab2/* and it is like Rich is saying:
- the configuration files overwrite Actions which are done in PaperUI in every restart
- you can easily add the UIs you want in the UI-section (but also the bindings)
- manually installed bindings
bundle install *via the openhab-console stay - until you update your openHAB to a new snapshot/release - Marketplace bindings can be added to the addons.cfg and are kept even with an update of OH2
ad 4)
you can easily install them via PaperUI as instructed in the Marketplace, then retrieve their names and use them in addons.cfg:
# A comma-separated list of market extension to install (see https://marketplace.eclipse.org/)
market = binding-3421078
be sure to activate Marketplace in the first place (also in addons.cfg):
# A comma-separated list of miscellaneous services to install (e.g. "myopenhab")
misc = market