Improve template formating performances

What does this MR do and why?

Change beautifulsoup parser for html minifier : replace default html5lib by much performant lxml

feat(template.*): Improve template beautifier by 10%

MR acceptance checklist

• My code follows the style guidelines of this project
• I ran pylint and other linters for modified files
• I have performed a self-review of my own code and tested it
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• My code needed automated testing. I have added them (this is optional task)
• I have added user readable comment in the CHANGELOG