Have .gpirc preferences stay with conda environment

As a developer it's frustrating to have to modify/backup/restore the `.gpirc` file when switching between different conda environments. As a GPI user less familiar with command line tools, finding and editing `.gpirc` in the default location isn't trivial.

I propose a modification where:
- `.gpirc` is moved inside the conda environment, probably inside the `gpi` site-packages folder.
- GPI looks there first, then to the user's home directory
- A "modify GPIRC" option is added to the GPI menus to allow users to change these preferences without having to see the preferences file itself. This could just spawn a text editor with `.gpirc` open, or if we want to get a little fancier, could be a window for modifying the various options in a GUI format.