Nick/split cost usage window

[nickcurie]

What does this PR change?

• Splits window flag into two separate flags. One for determining historical usage, and another for determining costs.
  • This allows users to use reconciled cost data by passing a 48hr offset window.

Does this PR rely on any other PRs?

• https://github.com/kubecost/kubecost-cost-model/pull/1290

How does this PR impact users? (This is the kind of thing that goes in release notes!)

• Added separate usage and cost window flags

Links to Issues or ZD tickets this PR addresses or fixes

• https://github.com/kubecost/kubecost-cost-model/issues/1250

How was this PR tested?

Observed flags sending correct windows for both usage and cost

Have you made an update to documentation?

No

[michaelmdresser]

Shell convention is to use - separators instead of camel case and to prioritize brevity (in flag names).

Suggested change

	cmd.Flags().StringVar(&predictO.avgUsageWindow, "avgUsageWindow", "2d", "The window of cost data to base average usage on. See https://github.com/kubecost/docs/blob/master/allocation.md#querying for a detailed explanation of what can be passed here.")
	cmd.Flags().StringVar(&predictO.resourceCostWindow, "resourceCostWindow", "7d offset 48h", "The window of cost data to base resource costs on. See https://github.com/kubecost/docs/blob/master/allocation.md#querying for a detailed explanation of what can be passed here.")
	cmd.Flags().StringVar(&predictO.avgUsageWindow, "window-usage", "2d", "The window of Kubecost data to calculate historical average usage from, if historical data exists. See https://github.com/kubecost/docs/blob/master/allocation.md#querying for a detailed explanation of what can be passed here.")
	cmd.Flags().StringVar(&predictO.resourceCostWindow, "window-cost", "7d offset 48h", "The window of Kubecost data to base resource costs on. Defaults with an offset of 48h to incorporate reconciled data if reconciliation is set up. See https://github.com/kubecost/docs/blob/master/allocation.md#querying for a detailed explanation of what can be passed here.")

[michaelmdresser]

Excellent, thank you

[michaelmdresser]

NOTE: This cannot be released until v1.102 of Kubecost. Perhaps we should make a compatibility note in the README as part of this PR. I'll give it some thought.