Create env vars for the algorithm's scheduling parameters

[ahg-g]

What would you like to be added:

Env vars tune the algorithm's scheduling parameters

Why is this needed:

To allow tuning

Context: #423 (comment)

[kfswain]

This is also related to: #16

[kfswain]

/assign @kaushikmitr

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/assign @kaushikmitr

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[kfswain]

/assign

[ahg-g]

Addressed in #580