feat(timer): change period/delay storage

[finger563]

Description

• Update timer to use std::chrono::microseconds for storing period and delay to improve precision of timing across platforms (e.g. on MacOS).
• Add period_float and delay_float members which perform the conversion once to then be printed in logs later as needed.
• feat(x-plat): added build scripts for ease of use and ignore the lib/pc output directory

Motivation and Context

On MacOS, the existing use of std::chrono::duration<float> for the period and delay had odd behavioral issues, leading to no wait at all on the condition variable. This PR fixes that.

How has this been tested?

• Building and running the timer example on a QtPy ESP32 PICO
• Building and running the PC timer test on MacOS

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Hardware (schematic, board, system design) change
• Software change

Checklist:

• My change requires a change to the documentation.
• I have added / updated the documentation related to this change via either README or WIKI

Software

• I have added tests to cover my changes.
• I have updated the .github/workflows/build.yml file to add my new test to the automated cloud build github action.
• All new and existing tests passed.
• My code follows the code style of this project.