EJS/Handlebars/Pug are not really optional Dependencies

[kgierke]

Describe the bug
The documentation mentions that the template engines are optional dependencies which only need to be installed if necessary. Yet at the moment they are listed as peerDependencies in the package.json and therefore installed automatically since npm version 7.

To Reproduce
Steps to reproduce the behavior:

1. Install the package
2. Inspect node_modules to see that ejs, handlebars etc. have been installed.

Expected behavior
The optional peer dependencies shouldn't be installed.

Additional context
This can be solved by defining peerDependenciesMeta in the package.json:

https://docs.npmjs.com/cli/v8/configuring-npm/package-json#peerdependenciesmeta

[AlexDieRobe]

Handlerbar (^4.7.8) has some security vulnerability that are not patched at the moment.