merge README documentation to homepage documentation

[VladimirAlexiev]

• Please put https://atextor.de/owl-cli/ in the project properties. Same as put doc site (home page) in project properties owl-cli#13
• Move (at least) these 2 sections from README to the homepage https://atextor.de/owl-cli/main/snapshot/usage.html#write-command
  • https://github.com/atextor/turtle-formatter#nice-and-configurable-formatting
  • https://github.com/atextor/turtle-formatter#customizing-the-style

Why:

• info should be in one and only one place (I understand one documents library options and the other CLI params, but the subject matter is the same, and the params are named the same as the options)
• the README has good descriptions and examples that the homepage lacks
• the README tables cannot be read well on github:
  

[atextor]

Hi @VladimirAlexiev,
thank you for bringing this up. There is a long-standing but until recently undocumented plan to merge turtle-formatter into owl-cli, since the projects are so closely related. This will not only make it easier to find the right place to open an issue ;-) but also to streamline and better structure the documentation.
So I'd consider this issue a follow-up of atextor/owl-cli#20.