add a short conversational memory

[ml2068]

Dear, Ollama have cotext setting, would add this option to llm.ollama.option?
such as below:

Conventions
....
context: the context parameter returned from a previous request to /generate, this can be used to keep a short conversational memory
....
https://github.com/ollama/ollama/blob/main/docs/api.md
'''
func WithContext(ctx []int) Option {
return func(opts *options) {
opts.ollamaOptions.context = ctx
}
}
'''
so we no need to build up memory outside the ollama api.

thanks!