Allow create-append-anything to be easily disabled

[smbea]

Is your feature request related to a problem? Please describe.

There is currently ways to remove the create-append-anything feature (see forum). But they require some effort or aren't super straightforward.

We should provide a way to easily remove create-append-anything.

Describe the solution you'd like

Extract create-append-anything to separate extension.

• Create new extension and release - https://github.com/bpmn-io/bpmn-js-create-append-anything
• Remove from bpmn-js and release as breaking change - Remove create-append-anything #1873
• Add it to awesome list - chore(README): add bpmn-js-create-append-anything awesome-bpmn-io#21

Describe alternatives you've considered

Don't ship it with default Modeler. Users have to explicitly add it if they want to use it.

Additional context

There have been around 4 (or more) questions on how to disable this feature. It is clear that not all users want this.

[smbea]

I like the config option because it still makes the feature discoverable but easy to remove.

We could check the Modeler options and remove the module if createAppendAnything = false (https://github.com/bpmn-io/bpmn-js/blob/develop/lib/Modeler.js#L135), similar to what we did in camunda-bpmn-js.

[nikku]

What about the alternative: Making it an external module (an extension)? Would fit nicely into our existing story, too.

[smbea]

You mean a completely separate extension living in a different library? Or a module that lives inside bpmn-js but is not added as default.

The reason I liked the option above was because it's easily discoverable, whilst something that is hidden in bpmn-js may not be as much. But it is less clean code wise.

A completely separate extension would be basically the connectors extension, right? We would extract the create-append-anything module and potentially allow to set templates too (based on our previous conversation, it's something we want to provide outside of camunda-bpmn-js)

[nikku]

A completely separate extension would be basically the connectors extension, right?

Exactly.

If possible we should keep the core lean. The readme ("related") and/or our awesome list are places to discover these additional helpful extensions.