Remove WordPress widget and iOS 13 Today widget related code

[staskus]

Fixes #21519

Description

WordPress widget-related removals

• Removing WordPressStatsWidgets target, since we no longer support widgets on the WordPress app
• Removing WordPressIntents target, it's used for selecting a site for a widget - Initial changes to make the Today Home Widget customizable. #15397
• Removing target related code from Podfile
• Removing target related code from Fastfile
• Renaming WordPressStatsWidgets and WordPressIntents folders to JetpackStatsWidgets and JetpackIntents, updating places where the names are referenced (I looked for occurrences with grep)

iOS 13 widget-related removals

Targets and some of the code was removed with #19509, however, some of the code was still in the codebase and it created confusion whether it referenced iOS14 or iOS13 widgets

• Removing constants
• Removing stats and site information saving logic (iOS 14 widgets use different logic)
• Removing Today extension-related code

To test:

1. Open Jetpack
2. Login
3. Go to home screen, long tap, and select Jetpack
4. Add widget
5. Confirm information appears for a site
6. Long-hold widget
7. Confirm site can be changed
8. Change the site
9. Confirm that the data loads

Regression Notes

1. Potential unintended areas of impact

Breaking current widget behavior, breaking fastlane flows, breaking localization flows

2. What I did to test those areas of impact (or what existing automated tests I relied on)

Manual testing, CI, and code-reviews

3. What automated tests I added (or what prevented me from doing so)

None

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

	Warnings
⚠️	PR has more than 500 lines of code changing. Consider splitting into smaller PRs if possible.

Generated by 🚫 dangerJS

[wpmobilebot]

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

	App Name	WordPress Alpha
	Configuration	Release-Alpha
	Build Number	pr21521-0da1d27
	Version	23.2
	Bundle ID	org.wordpress.alpha
	Commit	0da1d27
	App Center Build	WPiOS - One-Offs #6989

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[wpmobilebot]

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

	App Name	Jetpack Alpha
	Configuration	Release-Alpha
	Build Number	pr21521-0da1d27
	Version	23.2
	Bundle ID	com.jetpack.alpha
	Commit	0da1d27
	App Center Build	jetpack-installable-builds #6031

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

[guarani]

Thanks for removing all @staskus!

I think we could remove isJetpack checks at some point. Also, I'm not sure if userDefaultsJetpackFeaturesDisabledKey is needed anymore unless it's used for sites without Stats (e.g. self-hosted). Either way, this might need further investigation but isn't a blocker here.