common : add llama.vim preset for Qwen2.5Coder1.5B

[danbev]

This commit adds a preset for llama.vim to use the default Qwen 2.5 Coder 1.5B model.

The motivation for this change is to make it easier to start a server suitable to be used with the llama.vim plugin. For example, the server can be started with the following command:

$ llama.vim --vim-qwen2.5-Coder-1.5B-default

Refs: https://github.com/ggml-org/llama.cpp/issues/10932