Export as .pcd

**Is your feature request related to a problem? Please describe.**
I am working with annotation of 3d-pointclouds. The data i have access to is in .las format. However, most annotation software only accepts .pcd or .bin - files.

**Describe the solution you'd like**
Adding support in PyntCloud.to_file() to export files as .pcd format

**Describe alternatives you've considered**
I've tried converting .las to .pcd using PDAL, but the interface is tedious, and the files cannot be uploaded to the annotation software for some unknown reason.

I've tried exporting to .bin - file, but in the process information about colors is lost

**Additional context**
Link to the annotation software I am using
https://3d.supervise.ly/

Start at PyntCloud.to_file() and trace how existing formats, including .las and .bin, are selected and written. Check how point colors are represented, then add .pcd export support and verify that color information is preserved in the resulting file.

Written by the indexing model from the issue text.