dcache-core: increase default unpins per time

Motivation:
After commit a8e0c4f, pins that regularly expire are handled by the
pools themselves without additional message triggers from PinManager.
The default value of 200 unpins per time (default 1 minute) now only concerns files that are manually unpinned.

This default value is still too small, and in first tests a value of 2k/minute should
be fine and not overwhelm the system.

Modification:
Increase the `pinmanager.max-unpins-per-run` value to 2000.

Result:
Larger unpin/time default value that should make the default behaviour more performant.

Target: master
Requires-notes: no
Requires-book: no
Patch: https://rb.dcache.org/r/14122/
Acked-by: Tigran Mkrtchyan

skel/share/defaults/pinmanager.properties

@@ -176,7 +176,7 @@ pinmanager.reset-failed-unpins-period=2
 #   operations that require contacting pools should at most be processed
 #   per unpin task execution. Use -1 for no limit.
 #
-pinmanager.max-unpins-per-run=200
+pinmanager.max-unpins-per-run=2000
 
 # Authorization file for tape protection
 pinmanager.authz.staging=${dcache.authz.staging}