Remove 'powered by' link and Planetarium

[Ipstenu]

Recommend removing the powered-by link as the website no longer exists

planet/venus/themes/classic_fancy/index.html.tmpl

Lines 107 to 109 in ed8c38a

	Powered by:<br>
	<a href="http://www.planetplanet.org/"><img src="images/planet.png" width="80" height="15" alt="Planet" border="0"></a>
	</p>

[Ipstenu]

Also this section:

https://github.com/fairpm/planet/blob/ed8c38aa3aa5bac3ef293a9d05b0cf9af414f9bc/venus/themes/classic_fancy/index.html.tmpl#L111C1-L122C5

None of those links work reliably anymore :(