Increase recommended Rust toolchain to 1.75.0

[mulkieran]

• [x] Fix any newly introduced compiler or clippy errors:

  • [x] devicemapper-rs
  • [x] libblkid-rs
  • [x] libcryptsetup-rs
  • [x] stratisd (CLIPPY_FIX=1 make clippy and refine procedure for automatically applying clippy changes)

• [x] Give karma for f39 Rust release: https://bodhi.fedoraproject.org/updates/FEDORA-2024-35263f6e42

• [x] Bump current development toolchain in GitHub workflows

  • [x] devicemapper-rs
  • [x] libblkid-rs
  • [x] libcryptsetup-rs
  • [x] stratisd
  • [x] stratis-cli

[mulkieran]

We can wait until tomorrow for the remaining steps.