[Durable] Implement retry policy support

[AnatoliB]

Feature documentation: Automatic retry on failure.

Usage sample:

$retryOptions = New-DurableRetryOptions `
                        -FirstRetryInterval (New-Timespan -Seconds 1) `
                        -MaxNumberOfAttempts 5 `
                        -BackofCoefficient 1.5 `                        # Optional
                        -MaxRetryInterval (New-Timespan -Seconds 20) `  # Optional
                        -RetryTimeout (New-Timespan -Seconds 60)        # Optional

Invoke-ActivityFunction -FunctionName ... -Input ... -RetryOptions $retryOptions

[Francisco-Gamino]

Code looks great. One minor comment. Other than that, LGM.

[Francisco-Gamino]

Should the last character in this line be a '{' instead of '('?

[Francisco-Gamino]

Thanks @AnatoliB for adding the link to the docs.

The timespan parameters for New-DurableRetryOptions cmdlet did not feel intuitive at first. However, after taking a look at the examples in our docs https://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-error-handling?tabs=csharp#automatic-retry-on-failure, there is a consistent experience across language offerings. Also, whenever the user does not pass a New-Timespan value, they will get a good error message from the parameter binder, so we are good to go.

[AnatoliB]

The timespan parameters for New-DurableRetryOptions cmdlet did not feel intuitive at first. However, after taking a look at the examples in our docs https://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-error-handling?tabs=csharp#automatic-retry-on-failure, there is a consistent experience across language offerings.

Yes, this is how I feel, too. We can incrementally improve this later by adding other parameters, or perhaps accepting numbers instead of timespan object and interpreting them as seconds automatically (if you have this kind of ideas in mind). But the basic minimal implementation should match the experience in other languages.

Thank you!