Add instruction to fix permissions for yarn home config dir

[natuk]

describe the issue

The dependency installation script for Ubuntu 18.04 installs yarn under sudo. This creates a ~/.config directory with root permissions. When I execute arches-project create my_project during installation I get a permission error. If I fix the permissions to my user and run it again, it works OK. I suggest adding a line to instruct the user to check that the permissions are correct before creating the project.

please add links to existing docs or code (if relevant)

New instructions should be added here:
https://arches.readthedocs.io/en/stable/installation/

which release does this issue concern?

stable

[natuk]

Just noticed that the permissions for the ~/.config dir are set to the user (not root) on Ubuntu 18.04 desktop. So this issue only applies to Ubuntu 18.04 server.

[mradamcox]

@chiatt If you are able to fix the ubuntu setup script (best case scenario), then we won't actually need to change the documentation.

[chiatt]

@mradamcox I briefly took a swing at fixing this in the install script. I tried installing without sudo, but ran into errors. I'm sure there's a solution, but a bit more time needs to be spent on it. I created an issue in Arches to address it there if we can: archesproject/arches#6805

[mradamcox]

I put some thoughts in that other ticket.