Add a simple cache for the loaded configurations from file
Add a simple cache for the loaded configurations from file

This helps cases where you load the same configuration file
in many (hundreds or thousands). It has to be time based
caching (and not stat) since in our use case, the stat() in
itself is also very slow and expensive.

PSUdaemon/trafficserver,rahmalik/trafficserver,pbchou/trafficserver,taoyunxing/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,rahmalik/trafficserver,rpufky/trafficserver,clearswift/trafficserver,clearswift/trafficserver,davidbz/trafficserver,duke8253/trafficserver,clearswift/trafficserver,reveller/trafficserver,bryancall/trafficserver,rpufky/trafficserver,taoyunxing/trafficserver,vmamidi/trafficserver,clearswift/trafficserver,chitianhao/trafficserver,taoyunxing/trafficserver,rpufky/trafficserver,davidbz/trafficserver,SolidWallOfCode/trafficserver,clearswift/trafficserver,clearswift/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,rpufky/trafficserver,bryancall/trafficserver,chitianhao/trafficserver,pbchou/trafficserver,bryancall/trafficserver,rpufky/trafficserver,clearswift/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,dyrock/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,rahmalik/trafficserver,davidbz/trafficserver,reveller/trafficserver,SolidWallOfCode/trafficserver,clearswift/trafficserver,duke8253/trafficserver,reveller/trafficserver,PSUdaemon/trafficserver,chitianhao/trafficserver,vmamidi/trafficserver,PSUdaemon/trafficserver,rpufky/trafficserver,rahmalik/trafficserver,reveller/trafficserver,persiaAziz/trafficserver,PSUdaemon/trafficserver,davidbz/trafficserver,pbchou/trafficserver,clearswift/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,persiaAziz/trafficserver,pbchou/trafficserver,rahmalik/trafficserver,persiaAziz/trafficserver,reveller/trafficserver,dyrock/trafficserver,dyrock/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,PSUdaemon/trafficserver,dyrock/trafficserver,PSUdaemon/trafficserver,persiaAziz/trafficserver,pbchou/trafficserver,rahmalik/trafficserver,rahmalik/trafficserver,reveller/trafficserver,dyrock/trafficserver,PSUdaemon/trafficserver,reveller/trafficserver,persiaAziz/trafficserver,taoyunxing/trafficserver,taoyunxing/trafficserver,reveller/trafficserver,dyrock/trafficserver,rahmalik/trafficserver,PSUdaemon/trafficserver,rpufky/trafficserver,persiaAziz/trafficserver,taoyunxing/trafficserver,duke8253/trafficserver,chitianhao/trafficserver,bryancall/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,pbchou/trafficserver,rahmalik/trafficserver,vmamidi/trafficserver,rpufky/trafficserver,taoyunxing/trafficserver,vmamidi/trafficserver,reveller/trafficserver,persiaAziz/trafficserver,duke8253/trafficserver,rpufky/trafficserver,davidbz/trafficserver,PSUdaemon/trafficserver,taoyunxing/trafficserver,taoyunxing/trafficserver