feat(normalisation): jsonNormalisation/v3 and fixes to jsonNormalisation/v1 as well as jsonNormalisation/v2 (#1218)

[jakobmoellerdev]

Note that this introduces a json normalization algorithm v3 which technically will break a minor release. however this is needed as we currently broke hashing and need to offer a working alternative. thus it should have been part of v0.19.0 already: #1214

What this PR does / why we need it

Package jsonv3 provides a normalization which is completely based on the abstract (internal) version of the component descriptor and is therefore agnostic of the final serialization format. Signatures using this algorithm can be transferred among different schema versions, as long as is able to handle the complete information using for the normalization. jsonv2 is the predecessor of this version but had internal defaulting logic that is no longer included as part of this normalization. Thus v3 should be preferred over v2. Note that between v2 and v3 differences can occur mainly if the "extra identity" field is not unique, in which case the v2 normalization opinionated on how to differentiate these items. This no longer happens in v3, meaning the component descriptor is normalized as is.

v2 and v1 were adjusted to accomodate the old(but new because forgotten) legacy behavior in legacy.go. Without this, old signatures would not work. This means this should be (at least partially) back-ported to the last minor versioned released without this correction.

Which issue(s) this PR fixes

This issue fixes #1214 and supercedes #1217 as a better solution longterm (by getting rid of the old normalization) and shortterm (by achieving full backwards compatibility + introducing a simple test case)

Note that this changes the default normalization algorithm to be jsonNormalisation/v3 instead of jsonNormalisation/v1 as it is important for users to migrate as soon as possible.

This is a backport of a93ecca in #1218