add backwards compat in Sherlock for SDK v1 & v2

[felixhaeberle]

Description

Several properties & APIs have been changed in SDK v2, making Sherlock responsible for migrating them properly where it uses them. For example, the usage of customApi vs the new meta object or languageTags getting replaced by locales

Proposal

Add backwards compat in code and plan how to phase out the SDK v1 syntax rather soonr than later.

[felixhaeberle]

look after how the plugin interface and the renaming of bundleId to messageId influences the behavior

[felixhaeberle]

this is an ongoing task where tests need to be established for sherlock to work for sdk v1 input, so this goal is to create unit tests which successfully load & emit a sdk v2 project from an sdk v1 "interface" / data

TODO:

• create sdk v1 mock data for a unit test within sherlock running on sdk v2

[samuelstroschein]

Language tags are migrated by the SDK to locales. The only thing Sherlock needs to do is call customAPI (because no app other than sherlock used it). The rest is the SDKs job.