[App size reduction] Use optimized images for documentation. Remove unused assets.

[iamgabrielma]

Part of WOOMOB-534

Description

This PR switches the images in woocommerce-ios/docs/ for optimized versions of the same image, as well as updating apicredentials-location.png, reducing their original size by ~75%

woocommerce-ios/docs/images/apicredentials-location.png
woocommerce-ios/docs/images/yosemite_general.png
woocommerce-ios/docs/images/storage.png
woocommerce-ios/docs/images/networking.png
woocommerce-ios/docs/images/yosemite_actions.png

We also remove the following unused assets:

woocommerce-ios/WooCommerce/Resources/Images.xcassets/woo-store-switcher.imageset
woocommerce-ios/WooCommerce/Resources/Images.xcassets/woo-mobile-sync.imageset
woocommerce-ios/WooCommerce/Resources/Images.xcassets/icon-scan.imageset

Testing information

• Documentation under the main project's page, networking.md, yosemite.md, and storage.md should still display the images.

Screenshots

• Example of main page using the new image for credentials:

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS Prototype by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS Prototype
	Build Number	pr15874-627b9bd
	Version	22.7
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	627b9bd
	Installation URL	34rg0i00bprn8

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[staskus]

woocommerce-ios/docs/images/apicredentials-location.png

✅ Still appears in README

woocommerce-ios/docs/images/yosemite_general.png

✅ Still appears in YOSEMITE.md

woocommerce-ios/docs/images/storage.png

✅ Still appears in STORAGE.md

woocommerce-ios/docs/images/networking.png

✅ Still appears in NETWORKING.md

woocommerce-ios/docs/images/yosemite_actions.png

✅ Still appears in YOSEMITE.md

We also remove the following unused assets:

✅ yes, these assets weren't used