PTO.observations_api submodule for p1, p2 and alternative phase automation

Release notes

Currently, a separate setup for p1, p2 (and alternative implementations at different telescopes) is needed to use the output of PTO. This can be merged into PTO itself.

Problem to solve

A way of using PTO output to add transit windows in p1 and p2.

Proposal

Create a submodule in PTO to link the output of transit windows calculation to the p1, p2 tools.

Intended users

Everyone who needs to utilize ESO p1 or p2 system.