Add cargo.toml formatting with taplo

[echevrier]

• best config to match coding guidelines
• according to https://github.com/integritee-network/worker/issues/957
• enforces formatting of Cargo.toml in the CI

[echevrier]

For me the PR title is a little misleading. It's not a cargo fmt but a taplo fmt . What do you think?

Add cargo.toml formatting with taplo ?