Add more examples to playground

[katauber]

• Add more examples to playground: resolves Collect & add more Playground examples #25
• Fix disabled editors: resolves Shared workflows have disabled Data and Fix/Flux editors #64
• Add package-lock.json to repo

[fsteeg]

Here are some things I noticed (this is actually a functional review):

• The dropdown should have some visual indication that unlike the other buttons, it's a dropdown (e.g. a triangle/caret pointing downwards)
• The currently selected sample name should be visible, e.g. in the dropdown (both this and the first point should come for free with a UI component using/corresponding to the <select> HTML tag)
• From a usage standpoint, it would be really nice to see the input data when using a URL, e.g. if the data editor would be filled by that data (but still remained grayed out)
• This issue is emphasized by the fact that currently, 6 of 8 examples read from a URL. What I imagined was to have the examples from the initial comment with Playground input data, to see input, transformation and output for these different workflows (except probably the OAI-PMH workflow, though an XML-input example would be nice too).
• The Web_Pica_to_MarcXML sample produces no output for me (this branch depends on metafacture-core 5.3.1); also the flux seems pretty complex for an example (Pica-to-Marc21-toMarcXml?)
• I think we discussed (but didn't write down?) the idea to include numbering in the example file names to allow a tutorial-like ordering of the examples

Not sure what to approach here and what to do in separate issues. I think our process was a bit off here, maybe because @TobiasNx was both functional reviewer (for the integration of examples in the Playground) and implementor (for the examples themselves), so there was no functional review for the examples. Or it's just a bad idea to do multiple examples at once. Maybe we should have, and should in the future, open individual issues for each individual example.

To move forward and avoid keeping this branch longer running, we could:

• Remove all but two examples with URL input here (e.g. keep OAI-PMH_MODS_to_JSON and Web_MarcXML-to-JSON, which were mentioned in the initial comment), merge and deploy this
• Open new issues for dropdown UI, display URL input, HTML-to-JSON example, each of the removed examples, and numbering

I've moved these workflows to a disabled/ subfolder and made a small tweak to allow folders under examples/ in 38c1eeb. We could then move them back when working on the new issues.

[dr0i]

The Web_Pica_to_MarcXML sample produces no output for me (this branch depends on metafacture-core 5.3.1)

Yes, this was fixed with metafacture/metafacture-core#435. Would it make sense to use metafacture-core version master-SNAPSHOT ? This implies to build metafacture-core locally, see #25 (comment). Did this for https://test.metafacture.org/playground/.

[katauber]

• The dropdown should have some visual indication that unlike the other buttons, it's a dropdown (e.g. a triangle/caret pointing downwards)
• The currently selected sample name should be visible, e.g. in the dropdown (both this and the first point should come for free with a UI component using/corresponding to the <select> HTML tag)

I deployed these changes to https://test.metafacture.org/playground/. @TobiasNx should re-do functional review because the dropdown menu changed. Please re-assign @fsteeg for code review afterwards.

• I think we discussed (but didn't write down?) the idea to include numbering in the example file names to allow a tutorial-like ordering of the examples

I remember later on we decided not to use numbers. We should discuss this again, if we want an issue for numbering the examples.

• Open new issues for dropdown UI, display URL input, HTML-to-JSON example, each of the removed examples, and numbering

Opened:

• display URL input: #72
• HTML-to-JSON example: Add HTML-to-JSON example #73

I did not openend an issue for each of the removed examples. Could please someone else (@fsteeg or @TobiasNx?) open the issues for these examples.