feat: improve bun plugin behaviour

[jkowalleck]

followup of #81 will be merged,
we need to update our docs:

• mention that this is also a bun plugin
• showcase the plugin for bun in the examples
• adjust the SBOM result:
  • the $metadata.tools[name=esbuild] only appears when run with esbuild
  • try to detect bun, and add an appropriate tools section ...
  • see fix: better plugin env detection #84
• improve bun compatibility
  • add typing for Bun
  • maybe even have an own plugin harness for bun??
  • To b researched: fetch loglevel not from initialOptions but from config -- where is buns loglevel defied?
  • see [WIP] feat: full bun compatibility #85
• add an own loglevel config -- Feat: Pluginconfig for loglevel #86