Add acknowledgements file

[szokeasaurusrex]

In order to comply with the open source licenses (e.g. Apache or MIT) of most of the crates we use, we need to provide attribution and a copy of the license along with any copies/redistributions of the crate code.

As the crates are compiled directly into the binaries we distribute, e.g. on the GitHub releases page, we also need to provide this acknowledgement with the binaries in the release.

To generate the acknowledgements file, we will use cargo-about, as this is the best tool I was able to find, which generates such license attributions files. We will also add CI checks to ensure the acknowledgments file remains updated as dependencies are added, removed, and updated.

[linear]

CLI-178

[szokeasaurusrex]

work in progress branch at https://github.com/getsentry/sentry-cli/tree/szokeasaurusrex/acknowledgements