Fix image names on iOS

[NathanaelA]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• You have signed the CLA.
• All existing tests are passing: https://github.com/NativeScript/NativeScript/blob/master/DevelopmentWorkflow.md#running-unit-tests.

What is the current behavior?

The image names on iOS have several discrepancies (and a couple missing); this brings all the image names back into the proper format.

What is the new behavior?

All image names are named the standard way. Missing images have been added.

[manoldonev]

test

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.