docs: add privacy manifest

[tomlongridge]

Goal

Adds a PrivacyInfo.xcprivacy file to describe BugSnag's data privacy and restricted API usage into the xcproject, SPM and Cocoapods configurations.

The declared usage matches our docs with the exception of the removal of the two violations that are being removed in the next release: https://docs.bugsnag.com/platforms/ios/appstore-privacy/#declaring-required-reasons-for-api-usage

Changeset

• Needed to bump Swift Tools to 5.3 to allow for resources elements.

[github-actions]

Bugsnag.framework binary size did not change - 712,768 bytes

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