Add breadcrumb for all articles

[biumiamy]

Have everything in one spot and link to different notebooks: https://github.com/C2DH/journal-of-digital-history/wiki/Guidelines

add name of notebook like tags:

• need to add explanation how to maintain

[biumiamy]

Proposal to change layer switch to on/off button type of mechanic

..and update button for Github (see before below)

Get rid of myBinder button as this will become obsolete?

[biumiamy]

or simplify it even more

(and invert Github btn?)

[inactinique]

I would not simplify too much: shoudl be explicitly written hermeneutics / narrative, so I'm for your (very elegant) first solution.

[biumiamy]

Implemented.