ENH: add web-based metadata entry with HTML/JS and `QWebEngineView`

[jsheunis]

This PR aims to add web-based metadata entry with HTML/JS and QWebEngineView.

[jsheunis]

I upgraded Pyside6 from 6.3.1 to 6.3.2, but this had no effect.

[jsheunis]

sorry @mslw that was an accidental request

[mih]

I would want to avoid importing JS assets into the repo. They are more or less just "binary" blobs that we do not intent to maintain. I see two ways:

1. provide an initialization routine that downloads those blobs into a local cache dir once needed
2. we turn the repo into an annex dataset and annex addurl these files

I'd prefer the latter ATM, but I did not think much about it.

[jsheunis]

1. provide an initialization routine that downloads those blobs into a local cache dir once needed
2. we turn the repo into an annex dataset and annex addurl these files

Although, that would always require internet connectivity when the metadata functionality is used, right? And we specifically want this to be functional while users are not connected?

[mih]

(1) Would need it once, yes. (2) would not. The assets are baked into a release as usual. They merely not pollute the repo (just their checksums).

[adswa]

EDIT: Updating to Pyside 6.4 solved this.

Maybe its something on my system, but I can see a metadata browser. Instead, I see two different errors.

The first is an uncaught attribute error thrown on the first invocation of self._add_list_item(form):

> /home/adina/repos/datalad-gooey/datalad_gooey/custom_metadata.py(60)__init__()
-> for form in form_data:
(Pdb) n
> /home/adina/repos/datalad-gooey/datalad_gooey/custom_metadata.py(61)__init__()
-> self._add_list_item(form)
(Pdb) 
Traceback (most recent call last):
  File "/home/adina/repos/datalad-gooey/datalad_gooey/custom_metadata.py", line 94, in _load_form
    self._browser.setUrl(qurl)
AttributeError: 'CustomMetadataWebEditor' object has no attribute '_browser'
> /home/adina/repos/datalad-gooey/datalad_gooey/custom_metadata.py(60)__init__()

The second seems to be a problem opening the browser, but I suspect its something on my system that might be the problem:

qt.webenginecontext: 

GLImplementation: desktop
Surface Type: OpenGL
Surface Profile: CompatibilityProfile
Surface Version: 4.6
Using Default SG Backend: yes
Using Software Dynamic GL: no
Using Angle: no

Init Parameters:
  *  application-name datalad 
  *  browser-subprocess-path /home/adina/env/gooey/lib/python3.10/site-packages/PySide6/Qt/libexec/QtWebEngineProcess 
  *  create-default-gl-context  
  *  disable-features DnsOverHttpsUpgrade,ConsolidatedMovementXY,InstalledApp,BackgroundFetch,WebOTP,WebPayments,WebUSB,PictureInPicture 
  *  disable-setuid-sandbox  
  *  disable-speech-api  
  *  enable-features TracingServiceInProcess 
  *  enable-threaded-compositing  
  *  gpu-preferences UAAAAAAAAAAoAAAQAAAAAAAAAAAAAAAAAABgAAAAAAAwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAgAAAAAAAAACAAAAAAAAAAAAAAAAAAAAAIAAAAAAAAAAgAAAAAAAAACAAAAAAAAAA= 
  *  in-process-gpu  
  *  use-gl desktop 

[1098597:1098718:1026/090720.746685:ERROR:nss_util.cc(286)] After loading Root Certs, loaded==false: NSS error code: -8018

In case someone else has seen this, I'd be curious to get some more insights on how I could make it work.