Split large inelastic data into chunks

[NickDraper]

This issue was originally TRAC 3063

for speed on limited laptops

This is a specific implementation for C2E in the first case.

[NickDraper]

@NickDraper (2011-06-27T08:20:12):
"New" tickets moved at the code freeze of iteration 29

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@NickDraper (2011-09-19T09:30:03):
Bulk move of tickets to iteration 31 at the iteration 30 code freeze

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@NickDraper (2012-01-09T09:41:59):
Moved to iteration 33 at iteration 32 code freeze

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@NickDraper (2012-04-30T14:10:07):
Moved at end of release 2.1

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@NickDraper (2012-08-10T12:43:06):
Moved at the end of release 2.2

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@NickDraper (2012-10-28T11:38:20):
Moved to milestone 2.4

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@NickDraper (2013-04-29T09:49:26):
Moved to r2.6 at the end of r2.5

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@martyngigg (2013-07-15T08:46:42):
Batch move to 2.7

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@NickDraper (2014-02-14T11:04:53):
Bulk move to assigned at the introduction of the triage step

[martyngigg]

There seems to be little desire/resource for this at the moment.