Add Gemini API support as alternative to OpenAI in edamize()

[Divya1205]

Enable Gemini Integration for edamize()
We’re adding support for Gemini via ellmer, selectable with provider="gemini" or "openai"(default).

Here are the key references:

📘 chat_google_gemini() documentation
🔑 How to get and use a Gemini API key

[vjcitn]

Thanks for this. There are a few changes needed. First, please bump the version in DESCRIPTION whenever new code is submitted. Second, please add yourself as a contributor in DESCRIPTION. Third, it was my impression that the changes are to accommodate users who do not have OPENAI_API_KEY available. But a nontrivial amount of code still checks for that specifically instead of branching when GEMINI_API_KEY (?) is found set instead. I can help with these changes but let me know if you want to tackle them.

[vjcitn]

See the comment I added above. Additionally

> content2 = readRDS(system.file("rds/IRangesOVdata.rds", package="biocEDAM"))
> lk2 = edamize(content2$focus)
Loading required namespace: reticulate
Error in py_module_import(module, convert = convert) : 
  openai.OpenAIError: The api_key client option must be set either by passing api_key to the client or by setting the OPENAI_API_KEY environment variable
Run `reticulate::py_last_error()` for details.

Enter a frame number, or 0 to exit   

1: edamize(content2$focus)
2: reticulate::import_from_path("curbioc.curbioc", path = tempdir(), convert =
3: import_from_path_immediate(module, path, convert)
4: import(module, convert = convert)
5: py_module_import(module, convert = convert)

even though I have GEMINI_API_KEY set. Let me know how you want to proceed.