Standalone IOC option

As a developer I would occasionally like to:
- deploy an IOC to a new system without the rest of the directory tree
- substitute an IOC on an existing system

If there is an existing EPICS distribution, then updating the IOC with a static build may work. However an IOC often references Db and protocol files from elsewhere in the build tree, and its st.cmd may similarly load parts from elsewhere. We could for example copy some of there small ascii files into each IOC area as part of the build process.

## Acceptance criteria

* discussion on if and how we may with to support this