Added documentation on the Cake for Rider plugin

[nils-a]

As with the blog post, this is mostly information from the readme.

Things that need to be changed, after the release and before the merge:

• There's a link (placeholder) to the plugin in the marketplace, that needs to be set correctly.

[nils-a]

@pascalberger @gep13 could you please have a look at it?

[pascalberger]

@nils-a Thanks for this 👍

I added some comments. How does it look with IntelliSense support in Rider?

[nils-a]

@pascalberger thanks for the review - I will implement the changes.

There is currently no support for IntelliSense in Cake for Rider - I will add a page, similar to https://cakebuild.net/docs/integrations/editors/visualstudio/intellisense

[nils-a]

@pascalberger I have added the correct url to the plugin in the Marketplace and rebased.

We could, technically, merge this in as soon as the plugin version in the marketplace has been approved. From that point on it would be possible to use the link provided in this commit to download the pre-release version manually from the Marketplace and "install from disc".
@pascalberger , @gep13 what do you think?

[nils-a]

@pascalberger I added your suggestions.

[pascalberger]

LGTM and ready to be merged once extension is available

[gep13]

LGTM!

[nils-a]

I'll send a ping when the current uploaded version (0.1.0-alpha.1) was approved (and then probably do a rebase, too).

[nils-a]

[pascalberger]

@nils-a your changes have been merged, thanks for your contribution 👍