Platform interface: Updates documentation surrounding location accuracy on Android

[JeroenWeener]

On Android, location accuracy is interpreted in a rather unintuitive way. Users of the plugin get confused, resulting in reports coming in where users complain about not receiving positions. The problem sometimes lies in the fact that they use LocationAccuracy.lowest. While this accuracy option might suggest that location updates come in quicker, or at least at the same rate as higher accuracy options, this is not the case. Location accuracy on Android is mapped in the following way:

Location accuracy	Android priority	Description
lowest	PRIORITY_PASSIVE	Ensures that no extra power will be used to derive locations. This enforces that the request will act as a passive listener that will only receive "free" locations calculated on behalf of other clients, and no locations will be calculated on behalf of only this request.
low	PRIORITY_LOW_POWER	Requests a tradeoff that favors low power usage at the possible expense of location accuracy.
medium	PRIORITY_BALANCED_POWER_ACCURACY	Requests a tradeoff that is balanced between location accuracy and power usage.
high+	PRIORITY_HIGH_ACCURACY	Requests a tradeoff that favors highly accurate locations at the possible expense of additional power usage.

This means that when using LocationAccuracy.lowest, the update frequency of the position stream becomes 0, unless another app asks for a location update.

In the future, we might want to separate the iOS and Android implementations in such a way that the API is not confusing to users in the way that it is now. This is quite the undertaking, however, and therefore we want to start by adding a note in the documentation. This PR adds the note in several locations where users may look during development.

Closes #1315.

Pre-launch Checklist

• I made sure the project builds.
• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is does not need version changes.
• I updated CHANGELOG.md to add a description of the change.
• I updated/added relevant documentation (doc comments with ///).
• I rebased onto main.
• I added new tests to check the change I am making, or this PR does not need tests.
• I made sure all existing and new tests are passing.
• I ran dart format . and committed any changes.
• I ran flutter analyze and fixed any errors.

[codecov]

Codecov Report

Patch has no changes to coverable lines.

Files Changed	Coverage
...terface/lib/src/geolocator_platform_interface.dart	ø

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[mvanbeusekom]

LGTM, thanks @JeroenWeener