refactor: enable fileendings separated by more than one dot

[mfranzke]

Closes #1030

Summary of changes:

• enhancing fileextensions list in packages/engine-twig/lib/engine_twig.js and packages/engine-twig-php/lib/engine_twig_php.js to even also include .html.twig besides .twig
• rework in packages/core/src/lib/object_factory.js to check for a configured multi-dotted file extension and remove this form one from variable this.fileName whereas replace it in this.fileExtension

[JosefBredereck]

This could be dangerous.
When pattern lab discovers multiple pattern engines, it will try to spawn the file found in the engine's folder located under _meta/head...
In that case, the file will not be found, and an error will be thrown here

patternlab-node/packages/engine-handlebars/lib/engine_handlebars.js

Line 116 in 4cf86b6

const metaFileContent = fs.readFileSync(

You can either catch the error and ignore it, or you revert it to its former state.

Another issue could be, that by chance the file will be taken, but the output for the twig file will be overwritten by the content of the hbs file. In that case, it could lead to an error when serving pattern lab because it has a different rendering engine.

[JosefBredereck]

I would rather look into the engineFileExtensions and when the config.patternExtension is included there, output the required file. (In that case, we need to read the file we deliver with the engine from the _meta folder and spawn it as the configured extension in config.patternExtension.