\# `No Data` Variant
This commit adds a new variant that the `Analysis.MoveForward`
function can return. This variant is used to indicate that there
isn't enough data to make a concrete decision about the rollout.
This is then coupled with the `Rollout.OkayScoreUntilNoData` to
move rollout forward until a specific point even when there is
no data so that data can actually be created. If no data
is present even after `OkayScoreUntilNoData` is reached, then
we rollback as we aren't making an informed rollout. If positive,
we move forward. If negative, we rollback.
\# Target Based Metric Analysis
In this commit, We add a new `ErrorRatioAnalyzer` through which we
calculate the success target percentage by doing
((totalRequests - errorRequests)/totalRequests) * 100 and compare it
with the target percentage provided by the user. This means users can
specify a target percentage (i.e 99%, etc) at which a new cluster
can be considered safe. We rollback, If it is less than that.
Signed-off-by: Tarun Pothulapati <tarun@gitpod.io>
