App Restructure - model migrations

[mradamcox]

A big update, covering many tasks described in #99, as well as a few other smaller tickets. To summarize:

• Add A new Place model that facilitates a hierarchical geography model, and also allows a Place to be attached to each volume as a "locale". Step toward fully replacing Regions which would close [Bug] Region bbox coordinates inconsistent, need attention #82.
  • This concept will allow bounding boxes to be placed on a comprehensive map for exploration, as well as some other nice things like setting default map extents in a few different contexts (this is not yet fully implemented though).
• A new map viewer /viewer/<place-slug> that aggregates all volumes for a given Place (e.g. city). Closes Create standalone map view for a volume. #49.
• URL parameter for extent on georeferencing interface that allows a preset extent to be passed into the map viewer. Closes [Request] Use Key Map/reference layers to zoom georeferencing interface. #95 (it's not exactly the same, but close enough!).
  • In the georeference link for documents/layers in a Volume summary prepopulate this param with the volume's extent.
• Fix item ordering in volume summary. Closes [Request] Alphabetical listing of volume documents by title #94.

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Most of all, this PR includes new Layer and Document models that combine the default GeoNode models (of the same names) with the "proxy" models I had created in the georeference app. There is also a management command update_models that takes the attributes and tiff/jpg files from the GeoNode model instances and creates instances of the new models with that data. This fully. All interfaces that used to pull layers into maps have been updated to use the GeoTIFFs from the new instances, passed through TiTiler. The Layer and Document detail pages, which are still default GeoNode templates, are no longer fully supported (though they have not yet been replaced). The Volume Summary, Viewer, Volume Trim, all use the new model instances.

The session locking system has been disabled on all of the three georeferencing interfaces, as the actual splitting and georeferencing workflows have not yet been fully updated to use the new model instances anyway, so it's better to have the live previews easily accessible just for fun in the meantime. The single layer Trim interface will be removed--it serves no real purpose going forward as layer trimming is now handled on a per-volume basis in the Volume Trim interface.

[mradamcox]

Update: I have gone ahead and added substantially more changes than I was planning on initially including here. Main reason being that I felt no rush to complete this merge, as activity on the site is so low that I've been comfortable running it on the app_restructure branch for a while anyway now. Finally, I'm ready to merge this into the main branch.

New features beyond what is mentioned above:

• GeorefSession and PrepSession run() methods are now reimplemented
• Document and Layer are now "locked" with new properties on the ItemBase model when a session is in progress.
• TrimSession and LayerMask models have been deprecated and completely removed from the system, in favor of the new Volume-level trimming/mosaicking procedure.
• SplitDocumentLink and GeoreferencedDocumentLink are deprecated and removed entirely.
• All references to geonode.documents.models.Document and geonode.layers.models.Layer have been removed and replaced with georeference.models.resources.Document / Layer where necessary
• A new Resource.svelte component replaces the default GeoNode Document and Layer detail pages. (It is not as full featured, but a good basis to build from). It generally has the same logic that was in InfoPanel.svelte, the latter component being effectively obsolete though retained for the time being.
• [Bug] Active but non-functional Undo button available on split documents #93 is effectively taken care of--the undo button has been removed for now from the Resource page
• [Bug] Document not showing session in progress during georeferencing #92 should now be handled
• Titiler is now the expected tileserver for all local geotiff layers
• More svelte components have been created as well, to replace the default index, navbar, and footer in Django templates. As a result of this, Page scrolls underneath the site menu #36 is now irrelevant.

Ultimately, two aspects of GeoNode remain in some form: user accounts (Profile) and Regions. Technically, Regions are no longer used, but they are still referenced in this code-base because their replacement, Place, needs a bit more work. User accounts/profiles will require another restructuring at a later date.