Allow alternative installation path

I start thanking you for all this effort to arrange all the software needed for PiDP11 into a more organized and understandable form. I was thinking something similar as I ordered my PiDP but then I discovered this repo and I'd like to contribute!

I'll open this (first) issue, sorry if this is not the correct place to open, in case just close it and maybe let me know how to collaborate in the future (if you are interested).

I've seen that there are some hardcoded paths in some sources that points to /opt/pidp11, would be great to make it configurable in order to move it to a better (non system-owned) directory, i.e. in some user's folder.

Don't know the "correct" way to manage this, an option would be to patch the various executables to read some configuration file that the user could use to decide the path.

Thanks again for all this work!