fetch gb2 enrollments in chunks of api_max_per_page
fetch gb2 enrollments in chunks of api_max_per_page

refs CNVS-3927

Hopefully the api_max_per_page size is going to be increased soon, this
will prevent us from being artificially limited at 100.

Test plan:
  * set your api_max_per_page setting to > 100
  * ensure that the pages fetched by gb2 match your api_max_per_page
    setting

Change-Id: Ia0468f182b83acb911f9d328b97e9f8cbd696364
Reviewed-on: https://gerrit.instructure.com/17893
Reviewed-by: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
QA-Review: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>

wrdsb/canvas-lms,redconfetti/canvas-lms,instructure/canvas-lms,matematikk-mooc/canvas-lms,eCNAP/CANVAS,tgroshon/canvas-lms,shidao-fm/canvas-lms,kyroskoh/canvas-lms,rup/Tarrax,samuels410/greatlakes-lms,ShreniiNepal/shrenii_lmp,utkarshx/canvas-lms,juoni/canvas-lms,whalejasmine/canvas-lms,snehakachroo1/LSI_replica,instructure/canvas-lms,sdeleon28/canvas-lms,fronteerio/canvas-lms,roxolan/canvas-lms,wrdsb/canvas-lms,samuels410/greatlakes-lms,shidao-fm/canvas-lms,Rvor/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,instructure/canvas-lms,wrdsb/canvas-lms,narigone/canvas,arrivu/qibla-ecampus,venturehive/canvas-lms,usmschuck/canvas,sfu/canvas-lms,narigone/canvas,Unow/ins,samuels410/greatlakes-lms,redconfetti/canvas-lms,jay3126/canvas-lms,Jyaasa/canvas-lms,redconfetti/canvas-lms,sdeleon28/canvas-lms,djbender/canvas-lms,dgynn/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,tgroshon/canvas-lms,shidao-fm/canvas-lms,SwinburneOnline/canvas-lms,merichar/canvas-lms,usmschuck/canvas,AndranikMarkosyan/lms,usmschuck/canvas,loganrun/pincan,greyhwndz/canvas-lms,greyhwndz/canvas-lms,Rvor/canvas-lms,fronteerio/canvas-lms,Jyaasa/canvas-lms,juoni/canvas-lms,va7map/canvas-lms,antoniuslin/canvas-lms,Unow/ins,arrivu/arrivu-lms,sli7246/canvas_branch,AndranikMarkosyan/lms,greyhwndz/canvas-lms,kyroskoh/canvas-lms,va7map/canvas-lms,HotChalk/canvas-lms,utkarshx/canvas-lms,redconfetti/canvas-lms,sli7246/canvas_branch,leftplusrightllc/canvas-lms,snehakachroo1/LSI_replica,ShreniiNepal/shrenii_lmp,ShreniiNepal/shrenii_lmp,shidao-fm/canvas-lms,loganrun/pincan,HotChalk/canvas-lms,leftplusrightllc/canvas-lms,landonwilkins/canvas-lms,venturehive/canvas-lms,Unow/canvas-lms,va7map/canvas-lms,tgroshon/canvas-lms,roxolan/canvas-lms,Rvor/canvas-lms,snehakachroo1/LSI_replica,instructure/canvas-lms,sdeleon28/canvas-lms,juoni/canvas-lms,arrivu/jigsaw-lms,fronteerio/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,venturehive/canvas-lms,landonwilkins/canvas-lms,wrdsb/canvas-lms,arrivu/arrivu-lms,AndranikMarkosyan/lms,loganrun/pincan,matematikk-mooc/canvas-lms,Jyaasa/canvas-lms,efrj/canvas-lms,HotChalk/canvas-lms,skmezanul/canvas-lms,wimemx/Canvas,sdeleon28/canvas-lms,antoniuslin/canvas-lms,sfu/canvas-lms,arrivu/qibla-ecampus,arrivu/qibla-ecampus,HotChalk/canvas-lms,leftplusrightllc/canvas-lms,Unow/canvas-lms,Rvor/canvas-lms,whalejasmine/canvas-lms,eCNAP/CANVAS,arrivu/arrivu-lms,arrivu/jigsaw-lms,SwinburneOnline/canvas-lms,merichar/canvas-lms,matematikk-mooc/canvas-lms,kyroskoh/canvas-lms,landonwilkins/canvas-lms,rup/Tarrax,matematikk-mooc/canvas-lms,jay3126/canvas-lms,arrivu/jigsaw-lms,sfu/canvas-lms,merichar/canvas-lms,wye0220/shindig-canvas,snehakachroo1/LSI_replica,skmezanul/canvas-lms,antoniuslin/canvas-lms,sli7246/canvas_branch,narigone/canvas,Unow/canvas-lms,utkarshx/canvas-lms,landonwilkins/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,juoni/canvas-lms,leftplusrightllc/canvas-lms,usmschuck/canvas,rup/Tarrax,tgroshon/canvas-lms,gbleydon/canvas-lms,instructure/canvas-lms,efrj/canvas-lms,samuels410/greatlakes-lms,arrivu/hoodemo,wye0220/shindig-canvas,venturehive/canvas-lms,efrj/canvas-lms,roxolan/canvas-lms,djbender/canvas-lms,skmezanul/canvas-lms,arrivu/hoodemo,arrivu/hoodemo,greyhwndz/canvas-lms,gbleydon/canvas-lms,eCNAP/CANVAS,instructure/canvas-lms,whalejasmine/canvas-lms,efrj/canvas-lms,skmezanul/canvas-lms,dgynn/canvas-lms,AndranikMarkosyan/lms,sfu/canvas-lms,fronteerio/canvas-lms,dgynn/canvas-lms,wimemx/Canvas,roxolan/canvas-lms,Jyaasa/canvas-lms,kyroskoh/canvas-lms,Unow/ins,ShreniiNepal/shrenii_lmp,jay3126/canvas-lms,eCNAP/CANVAS,va7map/canvas-lms,wye0220/shindig-canvas,gbleydon/canvas-lms,wimemx/Canvas,antoniuslin/canvas-lms,SwinburneOnline/canvas-lms,dgynn/canvas-lms,grahamb/canvas-lms,utkarshx/canvas-lms,instructure/canvas-lms,narigone/canvas,whalejasmine/canvas-lms,jay3126/canvas-lms,djbender/canvas-lms