Disable the quanta feature by default

[tatsuya6502]

This PR disables the quanta feature by default.

If it is manually enabled, quanta::Instant will be used for some performance critical operations in the cache instead of std::time::Instant.

The quanta crate is a high performance time measurement library and will be great for some use cases such as collecting performance metrics. moka used to use quanta::Instant all over the place by default. However, quanta is not very good for tracking cache entry expiration times because the time measurement can drift over time and it may not be monotonic on some specific hardware (#472). Therefore, using std::time::Instant is more appropriate for tracking entry expiration times.

As of v0.12.10, the quanta feature will not make any noticeable performance difference, but in the future when cache metrics are added, it will be useful to have this feature enabled.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.31%. Comparing base (d22f4f3) to head (f7d2d29).
Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #482   +/-   ##
=======================================
  Coverage   94.31%   94.31%           
=======================================
  Files          43       43           
  Lines       20490    20490           
=======================================
+ Hits        19325    19326    +1     
+ Misses       1165     1164    -1     

[tatsuya6502]

Merging.