* use runtime:: prefix for message-lane pallet traces

* renamed message-lane (module and primitives) folder into messages

* replace "message lane" with "messages" where appropriate

* add document

* Send message documentation

* Apply review

Co-authored-by: Svyatoslav Nikolsky <[email protected]>

Co-authored-by: Svyatoslav Nikolsky <[email protected]>

* Add option to relay for sending transfers to Millau chain

* Endow derived accounts on Millau chain

* Update message generator entrypoint script to send transfers

* Use correct command when sending messages

* Send Root messages from Root origin on source chain

* Wrap calls from Root Origin in Sudo Call

* Allow Root to send messages without paying fees

* Use correct variable when sending messages to Rialto

* Print warning if no message type is provided to script.

* Add note mentioning that certain source origins aren't supported yet

* Use correct runtime when initializing header sync

* Remove option to send messages as Root

* Remove endowment of derived Root accounts

* Fix indentation.

Co-authored-by: Tomasz Drwięga <[email protected]>

* High level docs - start.

* Clean up README

* Start adding details to high level docs

* More docs on the header sync pallet

* Testing scenarios document.

* Add some scenarios.

* Add multi-sig scenario.

* Start writing about message dispatch pallet

* Move content from old README into PoA specific doc

* Apply suggestions from code review

Co-authored-by: Andreas Doerr <[email protected]>

* GRANDPA for consistency.

* Describe scenario steps.

* WiP

* Add notes about block production and forks

* Update.

* Add sequence diagram for Millau to Rialto transfer

* Clean up header sync pallet overview

* Remove leftover example code

* Clean up testing scenarios and amend sequence diagram.

* Linking docs.

* Add some more docs.

* Do a bit of cleanup on the high-level docs

* Clean up the testing scenario

* Fix typos in flow charts

* Fix small typo

* Fix indentation of Rust block

* Another attempt ...