Release 1.5.7

• added social media meta tags and variables
• added github action for docker build process and arm support, issue #65
• improved loading performance, the graph linking will only be done at the first page load, issue #97
• provided a python script to perform as alternative for the link generation, issue #97
• included mermaid 10.3.0 via cdn as composer had issues to load it
• updated highlight.js to 11.8.0
• updated katex to 0.16.8
• updated jquery to 3.7.1
• fixed issue #74 (custom heading links)
• fixed heading references in links to other notes
• implemented copy code button issue #68
• added a little padding for the headers
• merged PR #102 (thx to @selfiens)
• seperated php composer into two files (npm-assets and php-assets)
• fixed issue #91