Enable fastembed as a local embedding vendor (#12)

* Prepend all Langchain-based embeddings with LC

* Provide vanilla OpenAI embeddings

* Add test for AzureOpenAIEmbeddings and OpenAIEmbeddings

* Incorporate fastembed

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Co-authored-by: ian_Cin <ian@cinnamon.is>

libs/kotaemon/pyproject.toml

@@ -11,7 +11,7 @@ packages.find.exclude = ["tests*", "env*"]
 # metadata and dependencies
 [project]
 name = "kotaemon"
-version = "0.3.9"
+version = "0.3.10"
 requires-python = ">= 3.10"
 description = "Kotaemon core library for AI development."
 dependencies = [
@@ -61,6 +61,7 @@ adv = [
     "elasticsearch",
     "llama-cpp-python",
     "pdfservices-sdk @  git+https://github.com/niallcm/pdfservices-python-sdk.git@bump-and-unfreeze-requirements",
+    "fastembed",
 ]
 dev = [
     "ipython",