WebHost, Multiple Worlds: fix images not showing in guides (#5576)

* Multiple: resize FR RA network commands screenshot

This is now more in line with the text (and the english version).

* Multiple: optimize EN RA network commands screenshot

The URL has changed, so it's a good time to optimize.

* WebHost, Worlds: fix retroarch images not showing

Implements a src/url replacement for relative paths.
Moves the RA screenshots to worlds/generic since they are shared.
Also now uses the FR version in ffmq.
Also fixes the formatting that resultet in the list breaking.
Also moves imports in render_markdown.

Guides now also properly render on Github.

* Factorio: optimize screenshots

The URL has changed, so it's a good time to optimize.

* Factorio: change guide screenshots to use relative URL

* Test: markdown: fix tests on Windows

We also can't use delete=True, delete_on_close=False
because that's not supported in Py3.11.

* Test: markdown: fix typo

I hope that's it now. *sigh*

* Landstalker: fix doc images not showing

Change to relative img urls.

* Landstalker: optimize doc PNGs

The URL has changed, so it's a good time to optimize.

worlds/smw/docs/setup_en.md

@@ -100,9 +100,8 @@ You only have to do these steps once. Note, RetroArch 1.9.x will not work as it
 1. Enter the RetroArch main menu screen.
 2. Go to Settings --> User Interface. Set "Show Advanced Settings" to ON.
 3. Go to Settings --> Network. Set "Network Commands" to ON. (It is found below Request Device 16.) Leave the default
-   Network Command Port at 55355.
-
-![Screenshot of Network Commands setting](/static/generated/docs/A%20Link%20to%20the%20Past/retroarch-network-commands-en.png)
+   Network Command Port at 55355. \
+   ![Screenshot of Network Commands setting](../../generic/docs/retroarch-network-commands-en.png)
 4. Go to Main Menu --> Online Updater --> Core Downloader. Scroll down and select "Nintendo - SNES / SFC (bsnes-mercury
    Performance)".