build(readme): Remove signed image section

Since I'm no longer using CodeNotary, the related section of the readme has been removed.

README.md

@@ -9,7 +9,6 @@ mariaDB.
 
 - [Quick Start](#quick-start)
   * [Pull the image](#pull-the-image)
-    + [Signed images](#signed-images)
   * [Run the image](#run-the-image)
   * [Create a database](#create-a-database)
     + [Root password](#root-password)
@@ -61,35 +60,6 @@ The examples in this document will refer to dockerhub, but know that anywhere yo
 see `asifbacchus/ab-mariadb-alpine:tag` you can use `docker.asifbacchus.app/mariadb/ab-mariadb-alpine:tag` to use my
 registry instead.
 
-#### Signed images
-
-I have abandoned using Docker's signing mechanisms in favour of [CodeNotary](https://codenotary.io). Not only are they free, they offer several big advantages including avoiding Docker's weird and over-complicated key management system. The only drawback is that verifying images requires you downloading their [client software](https://github.com/codenotary/vcn/releases) which is free to use and does not require an account for verifying images or anything else. On Linux, you can simply rename the downloaded file `vcn` and place it somewhere in your path like `/usr/local/bin`, make it executable and then you can verify this image. Here's an example, obviously you need to modify it for your environment:
-
-```sh
-# run commands as root
-sudo -s
-
-# download vcn to proper location
-wget https://github.com/vchain-us/vcn/releases/download/v0.9.9/vcn-v0.9.9-linux-amd64 -O /usr/local/bin/vcn
-chmod +x /usr/local/bin/vcn
-
-# make sure it works
-vcn --version
-
-# verify container image
-vcn authenticate docker://asifbacchus/ab-mariadb-alpine:latest
-```
-
-If you want to confirm the image is authentic before each run, you can do:
-
-```sh
-vcn verify docker://asifbacchus/ab-mariadb-alpine:latest && docker run ... docker://asifbacchus/ab-mariadb-alpine:latest
-```
-
-Since you are making verification a prerequisite to running the docker command (i.e. using `&&`), you can be sure that you are working with a verified and signed image.
-
-You can get more information on installing the client software for different platforms [here](https://docs.codenotary.io/guide/quickhelp.html#installing-the-codenotary-tools).
-
 ### Run the image
 
 The image has sensible defaults and can be run without setting many environment variables. In the example below, we will start MariaDB server and create an empty database called 'CompanyX', set a root password and create a user account for Jane Doe which has *full privileges* for the *CompanyX* database. Data will be stored in the named volume 'companyDB'.