Add Custom Transform Engine Archetype.

[silverskyvicto]

I'm submitting a ... (check one with "x")

[ ] bug report => search github for a similar issue or PR before submitting
[x] feature request

Request the addition of an Archetype to develop a Custom Transform Engine, as stated in the title.

Expected Behavior

In addition to the add-on, the Archetype of Custom Transform Engine is displayed.

Current Behavior

Only the add-on Archetype is shown.

Possible Solution

Add new Archetype

Additional information

From the following document, it looks like a general Spring Boot application, so if you create a jar or war file, it seems that both distribution zip and docker image can be used.

Common code for Docker based ACS transformers