Related to T2188

Multiple identifiers (of either kind) can be passed either directly on the CLI
or via stdin. In the latter case logical lines in stidn will be preserved in
stdout.

Closes T2112

... instead of only showing *responses*, without matching requests

in addition to /

as /walk is temporarily disabled for now

works for both random and non-random walks

Closes T2084

we need to fix T1969 before opening this up, and in most cases what one wants
is really /randomwalk anyway

Closes T1888

it is the only sane way to have decent semantics in presence of edge
restrictions, without having to visit twice all successors

Closes T2077

in wait for a migration to a more propre solution, i.e.,
https://docs.python.org/3/library/importlib.html#module-importlib.resources

it is a marginal dependency of LAW, for a fringe tool that we do not use

while at it, switch string formatting to f-strings