Remove Serializable from asyncphp/doorman

[emteknetnz]

asyncphp/doorman was previously moved to the silverstripe/doorman repo

doorman is used by symbiote/silverstripe-queuedjobs

doorman still uses the Serializable interface which requires the implementation of the deprecated serialize() and unserialize() methods.

For the rest of our code base that interface and those methods have since been removed and replicated with __serialize() and __unserialize() methods.

There is a unreleased 4 branch for doorman for CMS 5.

ACs

• Remove Serialize() from doorman
• Implement __serialize() / __unserialize() if required
• Create a 4.0 branches from 4 post merge
• Update the CMS 5 version of symbiote/silverstripe-queuejobs to use ^4 of doorman
• Remove serialize() / unserialize() from queuedjobs
• Release doorman 4.0.0-beta1
• Add doorman 4.x-dev/4.0.x-dev to the root of silverstripe/recipe-kitchen sink so that it gets released as part of 5.0
• Deprecate serialise() / unserialise() in doorman 3

PRs

• API Use new serialize API closure#1
• API Use new serializable API doorman#46
• API Remove deprecated code symbiote/silverstripe-queuedjobs#399
• DEP Add asyncphp/doorman recipe-kitchen-sink#42
• API Deprecate serialize methods doorman#47
• DOC Deprecated asyncphp/doorman methods developer-docs#200

[maxime-rainville]

I would be keen to better understand why we didn't pick this up when we first tag the CMS 5 Sink and how we found it later on.

[GuySartorelli]

Assigning back to @emteknetnz for the remaining ACs (tagging, etc)