Migrate User Guide to Remote Content from llm-d-infra (#69)

* Remove local guide.md and prerequisites.md - now fetched remotely

* Remote fetch the updated quickstart guides.

- Added new guide-related files to .gitignore for remote content integration.
- Removed local `arch.jpg` and `quickstart.md` files as they are no longer needed.
- Introduced new remote content sources for guide examples, prerequisites, inference scheduling, and more to enhance documentation.

Signed-off-by: Pete Cheslock <[email protected]>

---------

Signed-off-by: Pete Cheslock <[email protected]>

Author: petecheslock

.gitignore

@@ -7,4 +7,11 @@ build
 docs/community/contribute.md
 docs/community/code-of-conduct.md
 docs/community/security.md
-docs/community/sigs.md
+docs/community/sigs.md
+
+# Guide remote content files
+docs/guide/guide.md
+docs/guide/Installation/prerequisites.md
+docs/guide/Installation/inference-scheduling.md
+docs/guide/Installation/pd-disaggregation.md
+docs/guide/Installation/wide-ep-lws.md