Implements caching for the interpolations

[Radonirinaunimi]

This allows caching the interpolated results through the environment variable NEOPDF_ENABLE_CACHE.

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.26%. Comparing base (e820d93) to head (f730896).

Files with missing lines	Patch %	Lines
neopdf/src/caching.rs	43.47%	13 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #72      +/-   ##
==========================================
- Coverage   80.42%   80.26%   -0.16%     
==========================================
  Files          27       28       +1     
  Lines        4602     4632      +30     
==========================================
+ Hits         3701     3718      +17     
- Misses        901      914      +13     

Flag	Coverage Δ
capi	47.37% <66.66%> (+0.08%)	⬆️
python	49.59% <66.66%> (+0.06%)	⬆️
rust	82.39% <66.66%> (-0.22%)	⬇️

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[github-actions]

🚀 Benchmark Results 🚀

Here are the results from the benchmark run.

xfxq2                   time:   [275.93 ns 276.31 ns 276.77 ns]
Found 15 outliers among 100 measurements (15.00%)
  9 (9.00%) low mild
  3 (3.00%) high mild
  3 (3.00%) high severe

xfxq2s                  time:   [29.043 µs 29.264 µs 29.520 µs]
Found 2 outliers among 100 measurements (2.00%)
  2 (2.00%) high severe

xfxq2_members           time:   [311.10 ps 311.37 ps 311.71 ps]
Found 14 outliers among 100 measurements (14.00%)
  4 (4.00%) high mild
  10 (10.00%) high severe

[github-actions]

🚀 Benchmark Results 🚀

Here are the results from the benchmark run.

xfxq2                   time:   [272.61 ns 272.82 ns 273.07 ns]
                        change: [−1.0945% −0.8480% −0.5902%] (p = 0.00 < 0.05)
                        Change within noise threshold.
Found 5 outliers among 100 measurements (5.00%)
  2 (2.00%) high mild
  3 (3.00%) high severe

xfxq2s                  time:   [29.544 µs 29.641 µs 29.741 µs]
                        change: [−1.4289% +0.8170% +3.1419%] (p = 0.52 > 0.05)
                        No change in performance detected.
Found 26 outliers among 100 measurements (26.00%)
  9 (9.00%) low severe
  5 (5.00%) low mild
  4 (4.00%) high mild
  8 (8.00%) high severe

xfxq2_members           time:   [627.65 ps 631.88 ps 636.54 ps]
                        change: [+100.29% +101.10% +101.88%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 17 outliers among 100 measurements (17.00%)
  2 (2.00%) high mild
  15 (15.00%) high severe