Add missing information for iOS

[mosabab]

closes #149

Platforms affected

IOS

Motivation and Context

Add missing information regarding this plugin for ios geolocation requirements.

Description

Add missing information, by describes the reason that the app accesses the user's location in different situations.

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[mosabab]

Hello @breautek , I also update this documents with missing information, please review it. Thanks

[mosabab]

Update readme

[mosabab]

Please review it

[mosabab]

Please review it now and check if everything is ok

[patrizi]

Hi,
I report that the problem is back.

This is what Apple write me:

ITMS-90683: Missing Purpose String in Info.plist- Your app's code references one or more APIs that access sensitive user data. The app's Info.plist file should contain a NSLocationAlwaysUsageDescription key with a user-facing purpose string explaining clearly and completely why your app needs the data. Starting Spring 2019, all apps submitted to the App Store that access user data are required to include a purpose string. If you're using external libraries or SDKs, they may reference APIs that require a purpose string. While your app might not use these APIs, a purpose string is still required. You can contact the developer of the library or SDK and request they release a version of their code that doesn't contain the APIs. Learn more (https://developer.apple.com/documentation/uikit/core_app/protecting_the_user_s_privacy).

My configuration is:
platform ios 5.1.1
cordova-plugin-geolocation 4.0.2 "Geolocation"