Refresh reference/bindings/ website pages. (#14380)

This updates the "API bindings" category of the website, focusing on:

* Which languages have API bindings, and which features those bindings
support
* Explaining API concepts with diagrams (docstrings -> reference pages
would be cool too: https://github.com/openxla/iree/issues/5477)
* Showing how to depend on IREE to use those APIs (the mechanics of
using shared libraries and C/C++ sources)
* **NOTE**: This is not fully finished yet, but I think it's ready to
checkpoint and publish as-is

|  | |
|--------|--------|
| Current section | https://openxla.github.io/iree/reference/bindings/ |
| Preview of this PR |
https://scotttodd.github.io/iree/reference/bindings/ |

I'm also removing the (empty) `bindings/tensorflow-lite/` page. I'm not
aware of anyone using those bindings, and the source should have enough
comments for a motivated user to find their way :crossed_fingers:
(closes https://github.com/openxla/iree/issues/5462).
diff --git a/docs/website/mkdocs.yml b/docs/website/mkdocs.yml
index 64affe2..1431d9a 100644
--- a/docs/website/mkdocs.yml
+++ b/docs/website/mkdocs.yml
@@ -139,9 +139,8 @@
       - "reference/index.md"
       - "API bindings":
           - "reference/bindings/index.md"
-          - Runtime C API: "reference/bindings/c-api.md"
+          - C API: "reference/bindings/c-api.md"
           - Python: "reference/bindings/python.md"
-          - TensorFlow Lite: "reference/bindings/tensorflow-lite.md"
       - "MLIR dialects":
           - "reference/mlir-dialects/index.md"
           # Note: these files are generated by generate_extra_files.sh.
@@ -201,7 +200,6 @@
         "bindings/index.md": "reference/bindings/index.md"
         "bindings/c-api.md": "reference/bindings/c-api.md"
         "bindings/python.md": "reference/bindings/python.md"
-        "bindings/tensorflow-lite.md": "reference/bindings/tensorflow-lite.md"
 
         # "blog/" moved under "community/"
         "blog/index.md": "community/blog/index.md"