Create video guide for spatialLIBD web applications

[lcolladotor]

We want to create a collection of short videos (likely shared on YouTube) demonstrating how to use the different features of the spatialLIBD interactive websites. We will collate these videos into a new user guide (a new vignette) and link to it as part of the default documentation for new web applications.

Some of these videos will be inspired by actual use cases we hear from our users using publicly available web applications.

This will be an evolving process as new videos will have to be made to reflect new features added to spatialLIBD.