Update CONTRIBUTING.md

[merks]

Add a badge-styled link to the CDT configuration and simplify the setup description.

[merks]

@jonahgraham @ruspl-afed

I've added the badge-styled link to the configuration. I've commented out the section with detailed steps because the configuration automates all those steps and because the page opened by the link also has all these instructions.

The description on that page has a description specific to CDT.

It comes from here:

cdt/releng/CDTConfiguration.setup

Lines 37 to 49 in 455f7fc

	<description>
	&lt;p>
	The &lt;a href=&quot;https://www.eclipse.org/cdt/&quot;/>Eclipse C/C++ Development Tools&lt;/a> configuration provisions a dedicated development environment
	for the complete set of source projects of the &lt;a href=&quot;https://projects.eclipse.org/projects/tools.cdt&quot;>CDT project&lt;/a>.
	&lt;/p>
	&lt;p>
	All the source projects from &lt;a href=&quot;https://github.com/eclipse-cdt&quot;>CDT's Github Repositories&lt;/a>
	are available, organized into working sets, and ready for contribution.
	&lt;/p>
	&lt;/p>
	Please &lt;a href=&quot;https://wiki.eclipse.org/Eclipse_Platform_SDK_Provisioning&quot;>read the analogous tutorial instructions&lt;/a> for the Eclipse Platform SDK's configuration for more details.
	&lt;/p>
	</description>

Best to use the properties view to edit this content so that the XML is properly escaped.

You can preview what it looks like in the hover:

[jonahgraham]

LGTM - I also deleted the commented out stuff.

[jonahgraham]

Thanks @merks