Add support to install as well as provide upgrade paths to unreleased test versions

[SrishT]

Description

Enabling testmode currently wither allows one to express an upgrade to an unreleased version OR a allows straight installation of an unreleased version, but not both. We need a way that allows a single value file to express both possibilities.

Importance

must have

Location

charts

Suggestions for an improvement

the value specified in testmode.version should be added to the version-map to allow deployment of this version as well as to allow upgrade from any version to this version. Furthermore, the testmode.fromVersion can be persisted to allow upgrade from any unreleased version to the unreleased version testmode.version