Add SetCacheDir API to customize disk cache directory.

[illidanstormrange]

No description provided.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 28.57143% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.97%. Comparing base (18befa6) to head (4cf3ce2).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/rendering/caches/DiskCache.cpp	28.57%	9 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3225   +/-   ##
=======================================
  Coverage   76.97%   76.97%           
=======================================
  Files         413      413           
  Lines       21910    21922   +12     
  Branches     6291     6298    +7     
=======================================
+ Hits        16865    16875   +10     
- Misses       3819     3824    +5     
+ Partials     1226     1223    -3     

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[shlzxjp]

dir如果不存在，没看到自动创建的逻辑