Adds a 'Canonical' field to the /block page.
note: this requires updating neptune-core in order to obtain the field
from neptune-core's /block_info rpc endpoint.
it was also necessary to change 'use neptune_core::<x>" statements to
'use neptune_cash::<x>'
We use axum route wildcards to merge duplicate page routes and handlers
into a single route and handler.
This makes the routes simpler/cleaner as well as the handlers, as there
is now just one of each for each html page.
Previous:
.route("/block/:selector", get(block_page))
.route("/block/:selector/value", get(block_page_with_value))
New:
.route("/block/*selector", get(block_page))
This is achieved by replacing PathBlockSelector with
BlockSelectorExtended which wraps BlockSelector to provide parsing for
height_or_digest/value. (which is needed for javascript-free input
form)
Changes:
* merge dup handlers for each of block, block_digest, block_info
* merge routes for same
* add BlockSelectorExtended and HeightOrDigest
* remove PathBlockSelector
