Update readme to reflect current status of project

[ahpook]

This took too long but better late than never.

I incorporated the "lyra vs X" tool comparison from the
main documentation site and pruned the roadmap/contribution
information. The rest of it can be preserved for future
generations.

[thallgren]

I think these changes are all good. One thing that comes to mind though is that since this effectively makes lyra a thing in the past "What was Lyra?", perhaps we should consider moving viable projects currently under "lyraproj" to another location.

[ahpook]

@thallgren check out the intro text at https://lyraproj.github.io for the rationale to keep them here - i would like to continue to have the project area for things such as dgo.

[thallgren]

My concern here @ahpook is that Lyra will be perceived as something that we've shut down. Nobody is interested in picking up potential pieces from something that is no longer supported (even if some pieces perhaps are supported. That part will be hard to convey convincingly).

[ahpook]

@thallgren if we move things in future, we can update the readme....