docs: update logo link, make logo smaller

### What does this PR do?

* PD does not support HTML in extension README's (yet)
* Reduces size of logo to 200px x 200px
* Moves the logo down below the title as well as makes it markdown only.

### Screenshot / video of UI

<!-- If this PR is changing UI, please include
screenshots or screencasts showing the difference -->

See markdown

### What issues does this PR fix or reference?

<!-- Include any related issues from Podman Desktop
repository (or from another issue tracker). -->

Related to containers/podman-desktop#7033

### How to test this PR?

<!-- Please explain steps to reproduce -->

N/A

Signed-off-by: Charlie Drage <charlie@charliedrage.com>

README.md

@@ -1,9 +1,7 @@
-<p align="center">
-  <img src="docs/img/logo.png" width="200" height="200">
-</p>
-
 # BootC (Bootable Container) Extension for Podman Desktop
 
+![](https://raw.githubusercontent.com/containers/podman-desktop-extension-bootc/main/docs/img/logo.png)
+
 Want to create a bootable operating system from a Containerfile? Download this extension!
 
 Easily go from container to VM / ISO-on-a-USB / RAW image!