Phase 2: Intro section

[sophiesage]

Added new architecture (new intro section, abbreviated previous collector intro page, added im directory) and hidden pages (what is the collector and choose a distribution) with content coming soon.

• I have read and followed the Contributing docs, especially the "First-time contributing?" section.
• This PR has content that I did not fully write myself.
  • I used AI and I have read and followed the Generative AI Contribution Policy.
• I have the experience and knowledge necessary to understand, review, and validate all content in this PR.¹

Changes for Issue: #8794
reopen of: #9373

Added a new Introduction Section:

• Copied content from _index.md of Collector
• Redid Collector page based on other OTel page updates (shorter length, connections to only distributions/
• Removed unused links from Collector main page
• Validated links for introduction sections
  Added img folder:
• Added img folder for image moved into introduction directory
  Added two hidden pages:
• Added "What is the Collector" Page, pending content (confirming)
• Added "Choosing a Distribution" Page, pending content (confirming)
• Both of these pages are linked in the introduction _index.md, but these can be removed if we are waiting on content
  Moved Architecture and Quick Start:
• These are both now under Introduction. Links can be added within paragraphs for better navigation

Let me know if there is anything else needed.

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Footnotes

1. Yes, I can answer maintainer questions about the content of this PR, without using AI. ↩

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: sophia-solo / name: sophia-solo (22bb735)
• ✅ login: sophiesage / name: sophiesage (1fbdc2d, 40a1de0, b840930)

[tiffany76]

Thanks @sophiesage! I'll give this a thorough review after KubeCon!