Added shapes viewer to the demo

[Gnomus042]

Some changes for one of the tasks in #44 - exposing shex schemas used for validation in ShExJ format.
Shapes are taken from shex.js internal representation in ShExJ, ids are extracted and shown in the list, as well as shape content when one of the shapes is selected. Here is the overview of how it would look:

It will be a little harder to display SHACL shapes, as to reconstruct them we need to parse the triples graph or rely on file serialization and format to fetch shapes and corresponding names, which would be unreliable. Alternatively, we can fetch used shapes from the server, for that we can put existing shapes to the DB instead of storing them in the filesystem. This will also allow exposing ShEx shapes in ShExC, which would be more readable.

Please let me know which option sounds better.

[danbri]

Fantastic—- thanks!

we have some fixes to merge in from ericP-changes. I suggest we do that first then merge in this PR.

[danbri]

@Gnomus042 does the updated package-lock.json work with this code?

[danbri]

Regarding your question I think it will be best if we can try to make it work with a simple static server as a shared base. In some contexts it makes sense to do things on server but for a default let’s try to have it work everywhere.