ICS-06: Solomachine Refactor (#821)

* update solomachine for 02-client-refactor

* fix client message handler fns

* address reviews

* continuted improvements

* Update spec/client/ics-006-solo-machine-client/README.md

Co-authored-by: Damian Nolan <damiannolan@gmail.com>

* Apply suggestions from code review

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>
Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>

* address colin review

* deprecate header sequence

* Apply suggestions from code review

Co-authored-by: Damian Nolan <damiannolan@gmail.com>

* address damian review

* formatting nits

Co-authored-by: Damian Nolan <damiannolan@gmail.com>
Co-authored-by: Carlos Rodriguez <carlos@interchain.io>
Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>
Co-authored-by: Carlos Rodriguez <crodveg@gmail.com>

Author: 4 people