[IMG282] UI for load data

• Original Gitlab story: IMG282

This PR introduces the following changes:

• updated MetaData and DataLoading class that serialize itself into json for output
• utility function to handle json input
• corresponding ui unit test based off PlayWright
  • please following this documentation to perform ui tests locally.

To test the two stages, copy the following code in a cell

import panel as pn
from imars3d.ui.stages.metadata import MetaData
from imars3d.ui.stages.dataloading import DataLoader

pn.extension("jsoneditor")

# build the pipeline
wizard = pn.pipeline.Pipeline(
    stages=[
        ("Metadata", MetaData),
        ("Load Data", DataLoader),
    ],
    debug=True,
)
# NOTE: we have to disable the axes linking as it will try to link with
# the "ct" viewers in the pipeline.
wizard.network.linked_axes = False
wizard.servable()

and you should be able to see the app in the cell

Alternatively, you can use this script at the root of the repo with panel serve test.py to view the two stages as a web app.

#!/usr/bin/env python3

import panel as pn
from imars3d.ui.stages.metadata import MetaData
from imars3d.ui.stages.dataloading import DataLoader

pn.extension("jsoneditor")

# build the pipeline
wizard = pn.pipeline.Pipeline(
    stages=[
        ("Metadata", MetaData),
        ("Load Data", DataLoader),
    ],
    debug=True,
)
# NOTE: we have to disable the axes linking as it will try to link with
# the "ct" viewers in the pipeline.
wizard.network.linked_axes = False

# setup via template
pn.template.FastListTemplate(
    site="iMars3D demo",
    title="Neutron Image Reconstruction",
    logo="HFIR_SNS_logo.png",
    header_background="#00A170",
    main=wizard,
    # theme="dark",
    theme_toggle=False,
).servable()

Known issue: The JSONEditor widget from panel does not auto refresh when its underlying dictionary is updated. Update: the issue is resolved by adding a manual trigger after dict update to force a redraw of the JSONEditor.