feat: Bring back GDAL and cli create-item

[alekzvik]

This is WIP, PR for visibility, and hopefully early feedback on questionable design choices.

Related to

#442

Description

I am bringing back GDAL because every geospatial library deserves GDAL as a dependency.

I am bringing back changes that were here before. Here is what is new:

• stac-gdal is now a crate
• stac-gdal::update_item can update your item's raster & proj extensions from the assets
• stac-gdal::ProjectionCalculations implements GDAL-based bounds calculations in WGS84 for Projections
• stac-gdal will try to use /vsicurl/ when reading your dataset
• CLI has a command create-item to create an Item from a href to an Asset
• stac::Bbox can be made from [f64;4] & [f64;6]
• Asset now has a "silent" field extensions and has an implementation of Extensions trait

Questionable decisions:

• Add silent extensions field to stac::Asset. The field is ignored by serde. It's not the greatest design, but saves a lot in ergonomics. Alternatively, I can try to implement the Extensions trait for Asset, but I am unsure about extensions_mut() and how to "mimic" it. As always, I'd appreciate any pointers here.
• Do we need a GDAL feature for the CLI?

Not done yet:

• CI
• proper docs
• Dependencies (I have not dug into gdal vs gdal-sys and which is better)
• CHANGELOGs

Checklist

Delete any checklist items that do not apply (e.g. if your change is minor, it may not require documentation updates).

• Unit tests
• Documentation, including doctests
• Git history is linear
• Commit messages are descriptive
• (optional) Git commit messages follow conventional commits
• Code is formatted (cargo fmt)
• cargo test
• Changes are added to the CHANGELOG

[gadomski]

Do we need a GDAL feature for the CLI?

I'd say yes, because many folks don't have GDAL on their system and I'd like our CLI to be usable generally.