bq27441: Add reset() method for hardware reset.

[nedseb]

Sub-issue of #78.

Context

The BQ27441 has a BQ27441_CONTROL_RESET (0x41) control command that performs a full hardware reset of the fuel gauge, distinct from soft_reset() (0x42) which only triggers a resimulation. The constant exists in const.py but no public reset() method exposes it.

TODO

• Add reset() method using execute_control_word(BQ27441_CONTROL_RESET)
• Add mock test
• Document the difference between reset() and soft_reset() in the driver

Reference

• BQ27441-G1 Technical Reference: Control() subcommands RESET (0x0041) vs SOFT_RESET (0x0042)

[nedseb]

Merged via PR #147 (sub-PR of #143).