v4.40.0-rc1: New PORTAL_BLOG_ Settings

Important

Integrate fix related to PORTAL_BLOG_SHOW_MAIN_IMAGE before v4.40.0.

What's Changed

• feat: new share on social media by default by @wesleyboar in #1155
• feat: PORTAL_BLOG_SHOW_MAIN_IMAGE by @wesleyboar in #1154
• fix(css): eliminate double @media in blog visual float layout by @wesleyboar in #1157
• fix(css): remove dead figcaption offset style by @wesleyboar in #1158

Full Changelog: v4.39.3-rc1...v4.40.0-rc1