Add delete layer method and tests in doc

[Atreyagaurav]

• I agree to follow the project's code of conduct.
• I added an entry to CHANGES.md if knowledge of this change could be valuable to users.

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I noticed this was not present, so I just added a crude implementation. Might be nice to add delete_layer_by_name option as well.

If there are more unimplemented methods, we can add as well.

[Atreyagaurav]

I don't think the CI fail is from my changes. Any idea what to do?

[Atreyagaurav]

The CI error says this:

 --- stderr
  thread 'main' panicked at gdal-sys/build.rs:250:17:
  No pre-built bindings available for GDAL version 3.11. Enable the `bindgen` feature of the `gdal` or `gdal-sys` crate to generate them during build.

[lnicola]

You can just comment out https://github.com/georust/gdal/blob/master/.github/workflows/ci.yml#L28. It looks like -latest is now 3.11.0, but 3.10 hasn't been published yet 😒.

[Atreyagaurav]

IDK why, commenting the line got me Invalid workflow file error, and CI didn't run. I tried a few alternative way to comment, thinking indent might have done it. I don't understand it, so for now I just removed the -latest line, Please remember to add it and 3.10.0 later.

[Atreyagaurav]

I squashed all commits, so it's easier to merge. This should be done now (once CI passes).

[lnicola]

I'll merge this after you squash. EDIT: nvm.