Use collapsible sections for connecting

[bkmgit]

Use collapsible sections for connecting, follows https://gist.github.com/pierrejoubert73/902cc94d79424356a8d20be2b382e1ab though can possible add a template for this. Addresses #40

[tkphd]

I like the result, but have concerns over the implementation.

• All of the options are drop-downs, leaving no default.
• It is preferable to use Markdown instead of raw HTML.

Please present the recommended practice (EdDSA) in full, then create a {: .callout} box mentioning that other crypto-systems or authentication methods may be employed. Inside, use {: .solution} blocks to create drop-down choices.

[bkmgit]

@tkphd Maybe we need something other than {: .solution} to create a dropdown. Made an issue for this in the styles repository carpentries/styles#595