feat: Add notebook for bigframes RAG (#1677)

# Description

This notebook showcases the power of BigFrames for building
production-ready RAG pipelines on Google Cloud. We leveraged BigFrames'
seamless integration with BigQuery and Vertex AI to efficiently process
and embed large text datasets.

.github/CODEOWNERS

@@ -71,6 +71,7 @@
 /generative-ai/genkit/postcard-generator                    @mattsday @GoogleCloudPlatform/generative-ai-devrel
 /generative-ai/gemini/evaluation/evaluate_langchain_chains.ipynb           @eliasecchig @GoogleCloudPlatform/generative-ai-devrel
 /generative-ai/gemini/use-cases/retrieval-augmented-generation/rag_qna_with_bq_and_featurestore.ipynb           @eliasecchig @lspatarog @GoogleCloudPlatform/generative-ai-devrel
+/generative-ai/gemini/use-cases/retrieval-augmented-generation/rag_pipeline_terabyte_scale_with_bigframes.ipynb           @lspatarog @eliasecchig
 /generative-ai/gemini/tuning/gemini_supervised_finetuning_text_classification.ipynb           @gabrielahrlr @eliasecchig @GoogleCloudPlatform/generative-ai-devrel
 /generative-ai/open-models/serving         @polong-lin @GoogleCloudPlatform/generative-ai-devrel
 /generative-ai/open-models/use-cases/cloud_run_ollama_gemma2_rag_qa.ipynb       @eliasecchig @GoogleCloudPlatform/generative-ai-devrel

.github/actions/spelling/allow.txt

@@ -76,6 +76,7 @@ DRV
 DVDs
 DWMWA
 Daniil
+Dedup
 DeepEval
 Depatmint
 Dexin
@@ -408,6 +409,8 @@ Takeaways
 Tbk
 Tbl
 Tencent
+Terabyte
+Terabytes
 Testables
 Tetsuo
 Tianli
@@ -521,6 +524,7 @@ barmode
 barpolar
 baxis
 bbc
+bbq
 beir
 bff
 bgswap
@@ -603,6 +607,7 @@ dbln
 dcg
 ddbb
 ddl
+dedup
 deepeval
 deepseek
 demouser
@@ -1004,6 +1009,7 @@ quadrotor
 qubit
 qubits
 quippy
+rag
 ragas
 ragdemos
 rahhhrr
@@ -1094,6 +1100,8 @@ takeaways
 tastetest
 tavily
 tencel
+terabyte
+terabytes
 termcolor
 terraform
 texting
@@ -1126,6 +1134,7 @@ tts
 tures
 typehints
 ubuntu
+udf
 uids
 ultrawide
 und