Allow the remote code path to be a relative path?

[dev-zero]

With HPC sites starting to use package managers like Spack or EasyBuild to provide codes, the paths to the executables become more cryptic. In many cases one also has to do a module load ... to enable the complete runtime required by codes, hence the requirement for the path to a remotely installed code being an absolute one becomes more a of a nuisance rather than actually providing more info and security (and since old versions of an installed code often do not run anymore or are removed after a system upgrade it becomes essentially meaningless).

Furthermore, the current implementation of the types.AbsolutePathParamType being used does local expansion of ~ according to

aiida-core/aiida/cmdline/params/types/path.py

Lines 41 to 46 in 7cea5be

	def convert(self, value, param, ctx):
	value = os.path.expanduser(value)
	newval = super().convert(value, param, ctx)
	if not os.path.isabs(newval):
	raise click.BadParameter('path must be absolute')
	return newval

which seems to be wrong due to the path being a remote path.

So, my suggestion would be to drop the requirement of the remote path.