Improve MOI optimizer

[tmigot]

A todo list to improve the connection with MOI (#152 ):

• increase coverage
• specify feasible point primal Add MOI wrapper #157 (comment)
• specify dual feasible Add MOI wrapper #157 (comment)
• add solver name
• add documentation
• add tutorial
• use SolverCore default solver instead of loading Percival in the tests

cc' @blegat @amontoison

[abelsiqueira]

Documentation?