feat: add cachelon (name pending) crates with multi-level caching abstractions

[schgoo]

Cachelon = Cache + Echelon

TODO more description

[github-actions]

⚠️ Breaking Changes Detected

error: failed to retrieve local crate data from git revision

Caused by:
    0: failed to retrieve manifest file from git revision source
    1: possibly due to errors: [
         failed when reading /home/runner/work/oxidizer/oxidizer/target/semver-checks/git-origin_main/2627e94555b3f837af373a6e9930fa063b1d8e87/scripts/crate-template/Cargo.toml: TOML parse error at line 9, column 26
         |
       9 | keywords = ["oxidizer", {{CRATE_KEYWORDS}}]
         |                          ^
       missing key for inline table element, expected key
       : TOML parse error at line 9, column 26
         |
       9 | keywords = ["oxidizer", {{CRATE_KEYWORDS}}]
         |                          ^
       missing key for inline table element, expected key
       ,
         failed to parse /home/runner/work/oxidizer/oxidizer/target/semver-checks/git-origin_main/2627e94555b3f837af373a6e9930fa063b1d8e87/Cargo.toml: no `package` table,
       ]
    2: package `cachelon` not found in /home/runner/work/oxidizer/oxidizer/target/semver-checks/git-origin_main/2627e94555b3f837af373a6e9930fa063b1d8e87

Stack backtrace:
   0: anyhow::error::<impl anyhow::Error>::msg
   1: cargo_semver_checks::rustdoc_gen::RustdocFromProjectRoot::get_crate_source
   2: cargo_semver_checks::rustdoc_gen::StatefulRustdocGenerator<cargo_semver_checks::rustdoc_gen::CoupledState>::prepare_generator
   3: cargo_semver_checks::Check::check_release::{{closure}}
   4: cargo_semver_checks::Check::check_release
   5: cargo_semver_checks::exit_on_error
   6: cargo_semver_checks::main
   7: std::sys::backtrace::__rust_begin_short_backtrace
   8: main
   9: <unknown>
  10: __libc_start_main
  11: _start

If the breaking changes are intentional then everything is fine - this message is merely informative.

Remember to apply a version number bump with the correct severity when publishing a version with breaking changes (1.x.x -> 2.x.x or 0.1.x -> 0.2.x).

[martintmk]

you should not depend on opentelemetry_sdk, that's very heavy dependency. opentelemetry should be enough

[schgoo]

I think I need it because I'm using SdkLoggerProvider in cachelon/src/telemetry/cache.rs

[martintmk]

We need to do something about this as I am aware the pure LoggerProvider is hard to box/store locally.

What I did in the seatbelt crate was to using tracing as logging front-end.