BEEFY High-level docs (#320)

* WiP

* Initial work.

* Fixes.

* Progress on round selection.

* Small update

* Some progress.

* Few fixes.

* Add session start block selection description

* Address review comments.

* Lean BEEFY

Author: tomusdrw

.editorconfig

@@ -11,6 +11,7 @@ trim_trailing_whitespace=true
 insert_final_newline=true
 
 [*.{yml,md,yaml}]
+max_line_length=100
 indent_style=space
 indent_size=2
 tab_width=8