Added blogpost "Incremental Knowledge Graph generation with YARRRML"

[ghsnd]

The pull requests adds a blog post on Incremental Knowledge Graph generation with YARRRML.

However

• Following the instructions to build the site resulted in an error (see below), so I couldn't actually test if it's OK and rendered well. Hence following remarks.
• I used mermaid to render graphs. Don't know if this works. It might be necessary to install this plugin first.
• The text refer to img/ldes.png (and added that file). I don't know if that works.

The post is also hosted internally at GitLab.

---

Build error:

Configuration file: /home/geraldh/projects/ldes/treegc-site/_config.yml
            Source: /home/geraldh/projects/ldes/treegc-site/pages
       Destination: /home/geraldh/projects/ldes/treegc-site/_site
 Incremental build: disabled. Enable with --incremental
      Generating... 
       Jekyll Feed: Generating feed for posts
  Liquid Exception: undefined method `tainted?' for "How to read a Linked Data Event Stream":String in /home/geraldh/projects/ldes/treegc-site/pages/_layouts/post.html
                    ------------------------------------------------
      Jekyll 4.1.1   Please append `--trace` to the `build` command 
                     for any additional information or backtrace. 
                    ------------------------------------------------
/home/geraldh/projects/ldes/treegc-site/vendor/bundle/ruby/3.2.0/gems/liquid-4.0.3/lib/liquid/variable.rb:124:in `taint_check': undefined method `tainted?' for "How to read a Linked Data Event Stream":String (NoMethodError)

      return unless obj.tainted?
                       ^^^^^^^^^