TASK: Improve ckeditor plugin migration to Neos 8.2 and up

[mhsdesign]

Description

currently an unreadable error is thrown which doesnt directly mention that it is a ckeditor plugin wich causes the error.
there are no upgrade instructions at: https://docs.neos.io/api/upgrade-instructions/8/upgrade-instructions-8-1-8-2

edit: there are actually instructions but i find them hard to understand 😂

related: #3287

[Description of the bug or feature]

Steps to Reproduce

1. [First Step]
2. [Second Step]
3. [and so on...]

Expected behavior

[What you expected to happen]

Actual behavior

[What actually happened]

Affected Versions

Neos:

UI:

You can get this information by running composer show or using the package management module within Neos.
The UI version can also be found inside the left sidebar after version 1.0.3.

[mhsdesign]

i think @mficzel and @ahaeslich can tell a song about how long it took them to find out that a ckeditor plugin in the neos.demo caused the odd console errors :/

[mhsdesign]

haha just found this message burried in the 8.2 blog post (hidden)

!!! A temporary breaking change!!!

Due to the update of our build environment, old Neos UI plugins that extend classes which are provided by the Neos core might throw errors due to an incompatibility. The extensibility package still converts JS classes to functions, and the browser throws an error if those try to extend an existing actual "class".

We are currently working on a solution for this, which should arrive in one of the next patch releases. There are of course other ways to make your plugin compatible already, without waiting for a patch. One is to convert the classes that extend core classes to functions instead.

We always try to prevent breaking changes in a minor release, sadly we saw this issue too late, as only some plugins are affected, and we cannot simply roll back the changes that lead to this issue.TODO: Provide link to tutorial