Make timer_tick_occurred a second long timer

[shaavan]

This PR updates timer_tick_occurred to operate on a second-long timer, providing finer timing control.

Reasoning:

1. This PR is the prerequisite of #3010, which introduces the ability to retry the InvoiceRequest message in a finite time if we have not received the corresponding BOLT12 Invoice back.
2. The retries need to be faster than a standard minute-long timer.
3. The discussion was between introducing a new counter vs changing timer_tick duration (see comment). This PR is an attempt at the second approach.