This commit adds lifetimes to the diff and realdom methods so consumers may borrow the contents of the DOM for serialization or asynchronous modifications.
This change switches back to the original `ctx<props>` syntax for
commponents. This lets lifetime elision to remove the need to match
exactly which lifetime (props or ctx) gets carried to the output. As
such, `Props` is currently required to be static. It *is* possible to
loosen this restriction, and will be done in the future, though only
through adding metadata about the props through the Props derive
macro. Implementing the IS_STATIC trait is unsafe, so the derive macro
will do it through some heuristics.
For now, this unlocks sharing vnodes from parents to children, enabling
pass-thru components, fragments, portals, etc.
