Editing - Add a new public method to check the form validity

[mdouchin]

This modification is a first step to improve the overall editing workflow, especially when creating child features for a not-yet existing parent object.

The future workflow could be

• open the creation form for a new parent object
• allow opening a creation form for 1 to many children
• validate the form data for each child to create, without having to save first the parent object (and the children). Do it also when modifying the child form data (we could keep the N forms in the DOM)
• Display the table of children "to be added or modified", with a look & feel like

UID	Feature ID	Label (automatically generated based on QGIS display expression)	Edit	Remove
96944c88-b947-4b69-a538-d9605193bd57	to be generated	Lampadaire EEOOFG tungstène	[edit]	[x]
96944c88-b947-4b69-a538-d96051923456	38	Lampadaire AABBCC diode	[edit]	[x]

• save the children form data in a single hidden text field, called for example children_data_layer_XXX which will store a table of JSON encoded form data
• when the user will Save the parent, in the PHP backend:
  • validate the new parent object
  • re-validate each child
  • save the parent, then save the children in batch. If a database error occurred, rollback all.

Funded by Commune d'Avignon

[github-actions]

The Lizmap project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 2 months and is being automatically marked as "stale".
If there is no further activity on this pull request, it will be closed in two weeks.

[github-actions]

The Lizmap project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 2 months and is being automatically marked as "stale".
If there is no further activity on this pull request, it will be closed in two weeks.

[github-actions]

The Lizmap project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 2 months and is being automatically marked as "stale".
If there is no further activity on this pull request, it will be closed in two weeks.

[github-actions]

The Lizmap project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 2 months and is being automatically marked as "stale".
If there is no further activity on this pull request, it will be closed in two weeks.

[github-actions]

The Lizmap project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 2 months and is being automatically marked as "stale".
If there is no further activity on this pull request, it will be closed in two weeks.

[github-actions]

The Lizmap project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 2 months and is being automatically marked as "stale".
If there is no further activity on this pull request, it will be closed in two weeks.

[github-actions]

The Lizmap project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 2 months and is being automatically marked as "stale".
If there is no further activity on this pull request, it will be closed in two weeks.