Manopt.jl Roadmap to 1.0

[kellertuer]

I feel that by now the overall architecture of Manopt.jl seems reasonably stable. In this issue I would like to keep track of (probably breaking) changes and improvements that would need to be done before we release a 1.0. I would currently assume there is at least one, if not two breaking releases before we go for 1.0.
This is also not meant as something that should be rushed – since any breaking change has effects on the eco system.

Feel free to recommend further points as comments below to be added to this list.

• set_parameter was designed a bit ad-hoc and should have a more consistent set of symbols to address semantic an not syntactic elements of sub-problems and sub-states. E.g. :p should become :Iterate.
• get_parameter should be used for accessing sub-solver states besides the result.
• Integration into JuMP
  • #264,
  • #273
  • #274
• Integration into Optimization.jl (SciML/Optimization.jl#712)
• All functions from src/functions should either be moved to ManifoldDiff (basic functions) or ManoptExamples (TV, Bézier) (#331).
• #381

Feel free to open more issues of what you would like to see as features within Manopt.jl 1.0