Create a dashboard for the nightly pipeline

[houtanb]

Add a pipeline dashboard with a view of:

• what data was pulled correctly or with an error last night
• for each question set, the number of resolved questions by source
• whether data is up-to-date (e.g. dbnomics pulls without an error, but the data is sometimes outdated)
• other views...

Make it publicly available, either on the site or on github

An internal version could show:

• the number of unresolved questions we have to sample from from each source
• their metadata
• other views...

h/t @simas-fri