Replace alloyeditor with a text input for the subtitle field in Blogs

• Type: Task
• Status: Closed
• Priority: Minor
• Resolution: Completed
• Affects Version/s: None
• Fix Version/s: Master
• Component/s: Blogs
• Labels: None
• Epic Link: fi-wysiwyg-variations
• Sprint: S03E21 - Vienna, S03E22 - Tokyo
• Git Pull Request: https://github.com/austinchiang/liferay-portal/pull/752

We would like to provide a coherent writing experience throughout liferay-portal.

Steps to reproduce:

• Navigate to Site > Content & Data > Blogs 
• Click on the + button to create a new Blog Entry

Proposal:

Use a simpler approach for the Title field in Blogs 

Given: We're on the Blog entry creation page
When: When I create a new Blog Entry
Then:

• The Subtitle field looks and behaves as an H1 tag
• The Subtitle field does not allow any formatting options (bold, italic...)
• Contents in the Subtitle field jump to another line when the size exceeds the container size
• Title field is not an instance of AlloyEditor

adolfo.perez, pablo.agulla, could you validate you're okay with this proposal?