Fill storage section in node operations chapter

node_operations.asciidoc

@@ -56,7 +56,8 @@ image::[images/raspiblitz.jpg]
   * Minimum Hardware requirements
   * CPU
   * RAM
-  * Storage (HDD, SSD)
+  * Storage : there are two main types of drives, HDDs and SSDs. HDDs are a lot cheaper and SSDs are a lot faster, but both would do the job. The fastest SSDs up to date use the NVMe protocol, but depending on your hardware they may not be better than the cheaper version, the SATA ones. As an example the Raspberry Pi 4 cannot benefit from them because of the limited bandwidth of it's USB port.
+  To choose the size, let's look at the blockchain. As of July 2020 it's size is ~330GB including the transaction index. If you want to have some margin available for the future or to install other stuff on your node, choose at least 1TB.
   * Bandwidth
 * Where will you host it (cloud hosting, VPS, own server, your laptop, RPi, MiniPC)
 * What OS will you use (Linux variant, Windows, other)

preface.asciidoc

@@ -184,6 +184,7 @@ Following is an alphabetically sorted list of all the GitHub contributors, inclu
 * Haoyu Lin (@HAOYUatHZ)
 * Hatim Boufnichel (@boufni95)
 * Imran Lorgat (@ImranLorgat)
+* Julien Wendling (@trigger67)
 * Kory Newton (@korynewton)
 * Luigi (@gin)
 * Patrick Lemke (@PatrickLemke)