This adds an observer which wraps around a Helm storage driver, to keep
track of the release metadata as written to the storage. This enables
you to work with, and compare release data as persisted by Helm.
Without having to rely on the result as returned by the Helm SDK. Which
at times of an error, may differ from last written state.
The observer does at present expect to be watching a single namespace,
and was designed without working with multiple releases simultianiously
into account, although this should theoretically still work.
The releases are at stored in a simple map by index storage key, which
are unique to the namespace. The `ObservedRelease` objects the keys hold are
overwritten on sequential writes to the same release object, and
returned by getter methods as deep copies.
This could theoretically be changed to observing e.g. all writes, I have
left this as a refinement TODO while actually implementing it in the
reconciler. The same goes for the included metadata, which might be not
all relevant.
Signed-off-by: Hidde Beydals <hello@hidde.co>