feat: Editor support for options configuration

[bitsandfoxes]

The goal is to have the least amount of steps between the config window and a user that just wants to write code.
The added options config tab allows the user to add the scriptable object that gets called during runtime initialization.
The button does:

1. Creates a script from a template at a user-selected location
2. Instantiates the scriptable object from the script and assigns it

Multiple button clicks allow for replacing of the script.
Already assigned scriptable objects do not get overwritten in the config window.

[github-actions]

	Fails
🚫	Please consider adding a changelog entry for the next release.

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

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Please add an entry to CHANGELOG.md to the "Unreleased" section. Make sure the entry includes this PR's number.

Example:

## Unreleased

- Editor support for options configuration ([#569](https://github.com/getsentry/sentry-unity/pull/569))

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[bruno-garcia]

Is this ready to be merged? We can merge the docs PR after this