Fix/api new changes

[kelcho-spense]

• added a typesafe env.ts file to enforce env variables in our api
• changed the cosmosdb.config.ts to cosmosClients.ts( changed the class format to reusable functions)
• added logs to keep track of the health of the API in the log folder
• added VectorDistance and similarityScore in retrieveRelevantChunks function in queryService.ts to optimize the revival of vector chucks
• added vectorEmbeddingPolicy and indexingPolicy in the creation of EmbeddingsContainer in cosmosClient.ts file
• moved generateEmbeddings.ts, generateTextVector.ts, readFileContent.ts and chunkDocument.ts files to utils folder
• separated app.ts with server.ts