[Feature]: Allow configurable_clientside_parameters for switching b/w finetuning models easily

[krrishdholakia]

The Feature

in the model_list, having a variable (like clientside_configurable_parameters with a default value of [] that contains a list of which litellm parameters can be overwritten by a client. This preserves the current behavior of no values overwritten by a client, but allows for new behavior of configuring variables that a client can override; this also gives the level of control we would want

model_list:
   - model_name: "anthropic/*"
     litellm_params:
       model: "anthropic/*"
#       api_base: "<default_api_base>" # [OPTIONAL]
       clientside_configurable_parameters: ["api_base", "base_url"]

Motivation, pitch

Allows devs to switch between finetuned models easily (changing api base), and allows admin to define which models + which params can have this behaviour (prevents security issues like https://huntr.com/bounties/4001e1a2-7b7a-4776-a3ae-e6692ec3d997)

Twitter / LinkedIn details

cc: @nathanluskey

[krrishdholakia]

We should probably be specific about what parameters we mean, updating to be configurable_clientside_auth_parameters

[krrishdholakia]

Updated to configurable_clientside_auth_params based on testing, it felt more intuitive