As suggested in PR 255207, introduce a new function called startmsg (name subject to change), which essentially is `check_startmsgs && echo`, to be used instead of `echo`, with the objective of silencing startup messages, as it is often forgotten to check_startmsgs before echoing.
Additional rc scripts mentioned in the PR will be submitted on a separate revision if/once this revision is accepted.
Eventually, init scripts in ports which echo directly should also be changed.
Given that we now boot under a second*, we may start thinking different ways to output (or not) boot progress to different types of users.
*Or pretty much close.