[raster][temporal] Add a brand new temporal mode: pixel value as temporal datetime

[nirvn]

Description

This PR implements a new temporal mode for raster layers which interprets each pixel as a datetime value. When rendering a raster layer using that temporal mode, pixels will be hidden whenever they fall outside of the temporal range attached to the render context.

In action, this is how it looks using a simple GLAD deforestation alerts geotiff:

Screencast.from.2024-04-04.09-52-39.webm

And here's how the setup UI looks like:

Interesting temporal use cases include:

• representation of land use change such as forest loss (as seen above)
• representation of flooding over time
• representation of movement cost (e.g. GRASS' r.walk)
• etc.

The implementation here is taken from @nyalldawson 's elevation surface representation functionality merged earlier this year. Thanks for the inspiration!

[github-actions]

🪟 Windows builds ready!

Windows builds of this PR are available for testing here. Debug symbols for this build are available here.

(Built from commit 2bc0adc)

[nyalldawson]

Great feature! This does make me think that we need a "single color" raster renderer to accompany this

[nirvn]

@nyalldawson , good idea. A single color renderer would be helpful even in a non temporal context here (eg show me all non-nodata as blue from a detected water/flooding dataset). It'd even be useful for elevation to define an elevation range area using a single color.

[nirvn]

@nyalldawson , comments addressed, thanks for the review.

[nirvn]

@nyalldawson , done.

[qgis-bot]

@nirvn
This pull request has been tagged as requiring documentation.

A documentation ticket will be opened at https://github.com/qgis/QGIS-Documentation when this PR is merged.

Please update the description (not the comments) with helpful description and screenshot to help the work from documentors.
Also, any commit having [needs-doc] or [Needs Documentation] in will see its message pushed to the issue, so please be as verbose as you can.

Thank you!

[qgis-bot]

@nirvn
A documentation ticket has been opened at qgis/QGIS-Documentation#9001
It is your responsibility to visit this ticket and add as much detail as possible for the documentation team to correctly document this change.
Thank you!