Set conda forge as default channel

[grallewellyn]

Add this to dockerfile: conda config --add channels conda-forge
Should work now because .condarc file is being created
If this works, remove from documentation that always need to run with -c conda-forge tag
@wildintellect Is this okay with you?

[wildintellect]

@grallewellyn I'd leave it in the docs for now, it's still best practices and doesn't break anything. This fix will just mean that if people forget it, or don't know about it yet they won't accidentally installed mixed packages and get their env stuck, or fail to install.

[grallewellyn]

Make sure there is .condarc file saying conda-forge when doing this

[anilnatha]

@grallewellyn (fyi) moved this ticket into Review/QA