Add configuration for ldap group sync in background

[stonezdj]

for better performance with large amount of ldap group

UI change in LDAP configuration: add a configuration item in LDAP Group Sync in Background

The screenshot is the compare between the sync group in background and sync group at login, with 1000 user groups and slow response ldap server, it will exceed 60 sec and timeout., when the sync group in background is true, the login is fast.

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[codecov]

Codecov Report

Attention: Patch coverage is 50.79365% with 31 lines in your changes missing coverage. Please review.

Project coverage is 69.01%. Comparing base (b7b8847) to head (5797279).
Report is 233 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #20672      +/-   ##
==========================================
+ Coverage   67.56%   69.01%   +1.44%     
==========================================
  Files         991      798     -193     
  Lines      109181    99788    -9393     
  Branches     2719        0    -2719     
==========================================
- Hits        73768    68866    -4902     
+ Misses      31449    27130    -4319     
+ Partials     3964     3792     -172     

Flag	Coverage Δ
unittests	69.01% <50.79%> (+1.44%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
src/lib/config/models/model.go	100.00% <ø> (ø)
src/lib/config/userconfig.go	66.88% <100.00%> (-1.10%)	⬇️
src/pkg/usergroup/manager.go	55.26% <33.33%> (+0.59%)	⬆️
src/core/auth/ldap/ldap.go	53.46% <51.78%> (+6.63%)	⬆️

... and 324 files with indirect coverage changes