Speedup workflow selfbuild and test using sccache

[NobodyXu]

• Use sccache to speedup workflow selfbuild and test.
• Add workflow cache-cleanup.yml to remove unused cache, since GHA does not allow
  main branch to use caches created by another branch.

TODO

• Set CARGO_BUILD_TARGET_DIR on workflow using sccache for better cache reuse. (cargo-install would automatically mkdir -p "${CARGO_BUILD_TARGET_DIR})
• Update cache-cleanup.yml from cargo-binstall
• Use sparse index: CARGO_REGISTRIES_CRATES_IO_PROTOCOL: sparse
  If this is not good enough, then also cache index:

   - name: Configure index cache
     uses: actions/cache@v3
     with:
        path: |
         ~/.cargo/registry/index/
         ~/.cargo/registry/cache/
         ~/.cargo/git/db/
       key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}-${{ inputs.cache-suffix }}
       restore-keys: |
         ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}-
         ${{ runner.os }}-cargo-index-

• Replace sccache-action with taiki-e/install-action
  and then setup environments required manually:

   - name: Configure sccache
     uses: actions/github-script@v6
     with:
       script: |
         core.exportVariable('ACTIONS_CACHE_URL', process.env.ACTIONS_CACHE_URL || '');
         core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '');

Signed-off-by: Jiahao XU Jiahao_XU@outlook.com

[NobodyXu]

The CI failed due to a bug in upstream rust-secure-code/cargo-auditable#87

[NobodyXu]

Closed since according to my experience, sccache with GHA backend doesn't provide much speedup at all.