Move clock logic in a module

See merge request !4

this module is in charge of periodically asking time (to time module) and asking diplay to display it.

Improve time sync so it won't leak when there is no connection

Closes #1

See merge request !3

autosync will only try once, no more failing loop. And no more risk of
concurrent calls.

should fix #1

Readme

See merge request !2

First version of code

See merge request !1

it manages time and display.
But not the configuration (wifi connection, hour offset, colors, ...)

which is basicaly gouge pcb :)

we need 21, only ot 20.

so the "foot" is lighter