Fetch blood sugar from /pebble

[nielsmaerten]

This is an experimental, unfinished commit. BloodSugar is now fetched from /pebble, instead of /entries.

TODO:

• [ ] Does this work when NS is set to mmol/l?
• [ ] Remove obsolete code
• [ ] Will parseFloat always work?
• [ ] What about calibration, meter tests, etc? Will they be parsed?

Description

Work in progress. Closes #61

Motivation and Context

See #61

How Has This Been Tested?

• [ ] Update existing tests
• [ ] Test on nightly with mg/dl
• [ ] Test on nightly with mmol/l
• [ ] Test on nightly with calibration
• [ ] Test on nightly with meter bg

Types of changes

New feature (non-breaking change which adds functionality)

Checklist:

• [ ] I've made my changes in a separate fix/ or feature/ branch
• [ ] My change requires a change to the documentation/website
• [ ] I have read CONTRIBUTING.md and CODE_OF_CONDUCT.md
• [ ] I've written tests to cover my change
• [ ] My change is passing new and existing tests