Kieker-1991 Fix URLs in the Kieker documentation

[shinhyungyang]

Pull Request

Hi, I tried to fix as much as possible, but some open questions remain. (Please see below.)

Contribution

This pull request provides the following contribution to Kieker

• Fixes for URLs
• Fixes for .rst format

Open Questions

• AspectLegacy (Visual Basic 6) Developer Guide tries to use resources from broken URLs such as https://build.se.informatik.uni-kiel.de/DynaMod-tools/trac/attachment/wiki/dynamod.aspectlegacy/DeveloperGuide/weaver_core_packages.png and alternative resources seem not available.
• Are we going to keep the parts on old artifacts (COM, .NET, etc)?
• Some links point to the binary distribution of the previous Kieker release, e.g.

Download Kieker complete archive https://github.com/kieker-monitoring/kieker/releases/download/1.15.4/kieker-1.15.4-binaries.zip

Therefore, it may be a good idea to provide the binary version of Kieker 2.0.0?

• Some links point to the old Javadoc on api.kieker-monitoring.org. The 2.0.0 (or 2.0.1) Javadoc needs to be published.