Add more settings for a block + code style fix

Hello!
I've added a few new settings to Global Gateway block:
1) Region

• None
• Select list (by default)
• select2boxes (if module is enabled)

1.1) Flags icons checkbox (if region widget set to select2boxes, and both select2boxes and flags modules are enabled)
Adds flags icons to countries.
2) Languages

• None
• Language switcher link (by default)

2.1) Behavior for untranslated content
2.2) Limit languages to region
2.3) Use native names
These settings are separate for each block. Older Global Gateway blocks will work well.

Also, I've made the small refactoring.