Add PulseClock driver

[nerdb0y]

Old site-wide clock installations used electrical pulses to synchronously advance (or reverse) clocks at the appropriate rates. These are sometimes known as secondary or slave clocks, eg: Seiko MC-009

This driver allows generation of appropriate pulses to actuate these clocks.

[openshwprojects]

very nice! Would you also be able to write a short guide on how to use this driver?
https://www.elektroda.com/rtvforum/forum51.html

We can merge it, but it would need to be disabled in obk_config by default

[MaxineMuster]

Yes, quite a cool idea!

The only remark from my side:
Maybe it turns out I'm mistaken, but I would assume the number of users to be not too high.
Therefore using 6 IOroles is filling up the list with entries not used by the majority of users making the dropdown list long.

Since [advertisement] as long as we don't hide unused IOroles like in #1826 [/advertisement] I would suggest to go the hard way setting the pins by command.
I know, 6 additional arguments are quite a challenge, but possible (maybe even by introducing a second command to set the pins (or movee the actual "optional" args from the startdriver command to a seperate one setting the pins with startdriver.)

Personally I like some "speaking" args, especially if there are many, like -Fwd P1 -FwdNeg p3 -FwdPos p4 -Rev p10 -RevPos p11 -RevNeg p17

With this approach you could even fit everything in one startdriver, because though it's long, you always know which parameter you are setting (and the order of arguments doesn't matter)

-Fwd P1 -FwdNeg p3 -FwdPos p4 -Rev p10 -RevPos p11 -RevNeg p17 -Res 60 -PulseOffs 0 -PulseMS 500 -MaxSec 43200

is equal to
-PulseMS 500 -Fwd P1 -Rev p10 -FwdNeg p3 -PulseOffs 0 -RevNeg p17 -FwdPos p4 -RevPos p11 -Res 60 -MaxSec 43200

[advertisement] I still hope, my PR #2024 will be accepted [/advertisement] but this is also possible in your own code.