Replace outdated tempdir dependency with tempfile

[teor2345]

Motivation

Zebra currently depends on 2 different versions of the rand crate, including an old version via tempdir.
The tempdir and rand dependencies are more than 3 years old.

If we remove outdated dependencies, Zebra will compile faster, its binaries will be smaller, and it will be more secure.

Tasks

1. Replace tempdir with tempfile::tempdir()
2. Remove the exceptions for these crates in deny.toml

[mpguerra]

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