Separated out Ingest and Query functionality of the server

[Eshanatnight]

Fixes #617.

Description

Separate out the Ingestion and Querying functionality of the server based on either a cli option --mode or an environment variable P_MODE.

Using a custom middleware to filter out non-accessible endpoints.

Changes

1. Update CLI to accept --mode flag.
2. Configuring routes to properly filter out the endpoints based on the mode.
3. Addition of middleware that properly filters out the endpoints.

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This PR has:

• been tested to ensure log ingestion and log query works.
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added documentation for new or modified features or behaviors.