config: Add profile script for fish shell

config: Add profile script for fish shell

Add support for setting $DEBUGINFOD_URLS automatically in the fish shell
similar to the profile scripts for POSIX and csh shells.

Makefile is set to install this into fish’s $XDG_DATA_DIRS vendor
directory instead of under /etc:
https://fishshell.com/docs/current/language.html#configuration-files

	* config/profile.fish.in: Set $DEBUGINFOD_URLS in fish shells.
	* configure.ac, config/Makefile.am: Include profile.fish in
	  install and uninstall targets.

Signed-off-by: Frederik “Freso” S. Olesen <freso.dk@gmail.com>