Sort imports according to PEP8 for gpslogger

[basnijholt]

Description:

I have sorted the imports for the gpslogger component according to PEP8 using isort.

I think it would be good if in the future we can add isort to the .pre-commit-config.yaml.
To do that I will first fix all sorting issues per component.

Black and isort do not play nice by default, however, using the following .isort.cfg config:

[settings]
multi_line_output=3
include_trailing_comma=True
force_grid_wrap=0
use_parentheses=True
line_length=88

it works.

This PR affects:

• homeassistant/components/gpslogger/__init__.py
• homeassistant/components/gpslogger/config_flow.py
• homeassistant/components/gpslogger/device_tracker.py

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly. Update and include derived files by running python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.