This MR does two things:

1. It introduces (and exports) the panicTrace and errorTrace functions in our Prelude, to be used as a drop-in replacement for panic and error. The glaring advantage is that they allow attaching a stacktrace of where the exception originated.

Compare, using panic in gargPassUserEasy':

Conversely, if we use panicTrace instead:

Now we know exactly where the error originated.

2. I have re-exported the original panic and error but I have marked them with the DEPRECATED pragma, so that if we compile gargantext and we still have instances of panic and error in the codebase, GHC will warn us (and stop compilation if -Werror is used):

cc @anoe and @cgenie