Pebble/Jade/Thymeleaf/Rocker/Freemaker template engines support

[tomaszmichalak]

Is your feature request related to a problem? Please describe.
Knot.x Template Engine supports Handlebars syntax. Other engines can be utilised:

• Freemarker
• Jade
• mvel
• Pebble
• Rocker
• Thymeleaf

Describe the solution you'd like
Use Vert.x modules inside Knot.x Template Engine: https://github.com/vert-x3/vertx-web/tree/master/vertx-template-engines.

[pun-ky]

handlebars templates are very strict but this strictness very often makes integration/implementation costs much bigger.. e.g no ability to set tmp variable in handlebars is very annoying and this causes very often a need for creating custom handlebars helper. using e.g pebble with better performance and more features could help a lot in delivering knotx based integrations faster.

[marcinus]

Vert.x modules have a direct caching and filesystem integration - this may not be desired as it will not be configurable

[marcinus]

Freemarker, Peeble, Thymeleaf, MVEL can be integrated without any significant changes.
Jade will require creating a custom TemplateLoader, but it should not be a problem.
Rocker is problematic - it's engine has filesystem callsand I have not found any workaround so far.

[pun-ky]

thanks for delivering it <3