Add legend with acronyms

See #1

profile/README.md

@@ -6,7 +6,7 @@ This page aims to synthetically document the software developed for the [LIFE RI
 
 ### Dataflow: the _big picture_
 
-![data flow](https://user-images.githubusercontent.com/33662631/146167126-e2f86adf-7836-4808-82e1-854017eb3c2a.png)
+![data flow](https://user-images.githubusercontent.com/33662631/146169367-d271bf3a-edd5-4c2f-a371-2ab7587a3c9a.png)
 
 The dataflow shown above can be clearly divided into a _left part_ and a _right_ part. The left part accounts for estabilishing data flows to the [Global Biodiversity Information Facility](https://www.gbif.org/) (GBIF), _an international network and data infrastructure funded by the world's governments and aimed at providing anyone, anywhere, open access to data about all types of life on Earth_ (source: ["What is GBIF?"](https://www.gbif.org/what-is-gbif) webpage). Notice that some data providers such as [iNaturalist](https://inaturalist.org/) and observations.be/waarnemingen.be publish their data on GBIF about alien species on a regular basis and so no mapping is needed in the context of LIFE RIPARIAS. The right part accounts for retrieving the standardized data from GBIF and so regularly maintain the RIPARIAS aggregated database. The early alert system is built upon it.