feat(content-band-list): add content-intro block & styles

[proeung]

Issue

Fixes - https://jira.sdlc.merative.com/browse/MERATIVE-781

Description

New

• This PR adds a new section/block called "Section - Content Band List" within the Franklin library that's needed as part of the migration from AEM to Franklin.
  • Sections > Section Content band list
• New block called Content Intro content-intro has been created to account for the two-column styling that matches with the design.

Design Specs

• Figma Link - https://www.figma.com/file/vw24IPXXt4vCh9BNumka9A/Web--Merative-Digital-Design-System-2.0?type=design&node-id=1459%3A18594&mode=design&t=4ccs9Lc8UZwT74t5-1

Test URLs

• Before (Changes from main): https://main--merative2--hlxsites.hlx.page/block-library/sections/section-content-band-list
• After (Changes from this PR): https://feat-content-band-list--merative2--proeung.hlx.page/block-library/sections/section-content-band-list

Testing Instruction

• Visit the preview page of the "Content List Band" - https://feat-content-band-list--merative2--proeung.hlx.page/block-library/sections/section-content-band-list
• Ensure that the different variations match with the design system/specs for all breakpoints (see Figma link)

[aem-code-sync[bot]]

Hello, I'm Franklin Bot and I will run some test suites that validate the page speed. In case there are problems, just click the checkbox below to rerun the respective action.

• [ ] Re-run PSI Checks

[aem-code-sync[bot]]

Page	Scores	Audits	Google
/block-library/sections/section-content-band-list

[aem-code-sync[bot]]

Page	Scores	Audits	Google
/block-library/sections/section-content-band-list

[aem-code-sync[bot]]

Page	Scores	Audits	Google
/block-library/sections/section-content-band-list

[proeung]

@sachinmesh I just pushed up a commit that should address all of your feedback. Can you take a look again?