Add Environment Variables to Disable Model Functionalities

[Josh-XT]

Introduce environment variables to disable the loading of various model functionalities in ezLocalai. The specific functionalities to be optionally disabled via environment variables include the LLM, vision model, image generation model, TTS model, and STT model. This feature will allow users to optimize resource usage and customize their environment based on specific needs.

[Josh-XT]

Created PR #53 to resolve issue #52: https://github.com/devxt-llc/ezlocalai/pull/53

[Josh-XT]

Created PR #54 to resolve issue #52: https://github.com/devxt-llc/ezlocalai/pull/54

[Josh-XT]

Additional changes have been applied to resolve issue #52. See PR #54.

[Josh-XT]

Additional changes have been applied to resolve issue #52. See PR #54.

[Josh-XT]

Additional changes have been applied to resolve issue #52. See PR #54.

[Josh-XT]

Additional changes have been applied to resolve issue #52. See PR #54.

[Josh-XT]

Additional changes have been applied to resolve issue #52. See PR #54.

[Josh-XT]

Additional changes have been applied to resolve issue #52. See PR #54.

[Josh-XT]

Additional changes have been applied to resolve issue #52. See PR #54.