pytest `snapshot_folder_name` and `allow_multiple_equivalent_writes_to_one_location`

[SDelgado-21]

• Original API documentation: https://kdoc.selfie.dev/selfie-runner-junit5/com.diffplug.selfie.junit5/-selfie-settings-a-p-i/

• Original junit5 implementation: https://github.com/diffplug/selfie/blob/main/jvm/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieSettingsAPI.kt

• Original Kotest implementation: https://github.com/diffplug/selfie/blob/main/jvm/selfie-runner-kotest/src/commonMain/kotlin/com/diffplug/selfie/kotest/SelfieSettingsAPI.kt

• SelfieSettings example: https://github.com/diffplug/selfie/blob/main/jvm/example-junit5/src/test/java/selfie/SelfieSettings.java

[nedtwigg]

We now have a SelfieSettings, but there are two parts missing:

https://github.com/diffplug/selfie/blob/f1325e86308984401ecc86323f4d2d2e2b4f1d81/python/pytest-selfie/pytest_selfie/SelfieSettingsAPI.py#L15-L23

Users should be able to set them like so:

https://github.com/diffplug/selfie/blob/f1325e86308984401ecc86323f4d2d2e2b4f1d81/python/pytest-selfie/pytest_selfie/SelfieSettingsAPI.py#L10

Right now our docs say something like this:

If you want the disk snapshots to live in a different folder, set snapshotFolderName using

whatever we have to say there should be accurate