A new battery screen

[Samarth2898]

Description

Added a new screen to track battery-related information. It can be accessed using the 'battery' flag.

Fixes #126

Type of change

• [x] New feature (non-breaking change which adds functionality)
• [x] This change requires a documentation update

Checklist:

• [x] I have read the contribution guidelines and followed it as far as possible.
• [x] I have performed a self-review of my own code (if applicable)
• [x] I have commented my code, particularly in hard-to-understand areas (if applicable)
• [x] I have run go fmt on my code (reference)
• [ ] I have made corresponding changes to the documentation (if applicable)
• [x] My changes generate no new warnings
• [ ] Any dependent and pending changes have been merged and published