[SSSD] [sssd PR#5546][opened] kcm: add GET_CRED_LIST for faster iteration

[pbrezina]

   URL: https://github.com/SSSD/sssd/pull/5546
Author: pbrezina
 Title: #5546: kcm: add GET_CRED_LIST for faster iteration
Action: opened

PR body:
"""
For large caches, one IPC operation per credential dominates the cost of
iteration. Instead transfer the whole list of credentials to the client in
one IPC operation.

Resolves: https://github.com/SSSD/sssd/issues/5545

This is a continuation of https://github.com/SSSD/sssd/pull/5375. The first
pull requests addressed bottlenecks in sssd-kcm and reduced the test case
run time from 30 minutes to 2 minutes, this new operation takes it down to
9 seconds.
"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/5546/head:pr5546
git checkout pr5546