Add "pdal" to rosdistro/base

[jlblancoc]

PDAL is a C++ library for translating and manipulating point cloud data.

It has potential interest for some ROS packages related to mapping / pointcloud processing, including readers/writers to .las/.laz files.

It's already packaged for Debian / Ubuntu. I have to check whether it's packaged for other distros and then will try to make the PR myself.
Just wanted to left this here in case someone can take a look and create the PR before that.

[clalancette]

Sounds good, thanks. Please feel free to open a rosdep PR when you are ready.

[jlblancoc]

@clalancette It seems the package was removed from Debian 2 years ago, despite it's been maintained in Ubuntu (!), so I guess it's not allowed to add a debian: null entry, right? :-(