Support multiple OpenAI compatible providers (#34212)

TODO
- [x] OpenAI Compatible API Icon
- [x] Docs
- [x] Link to docs in OpenAI provider section about configuring OpenAI
API compatible providers

Closes #33992

Related to #30010

Release Notes:

- agent: Add support for adding multiple OpenAI API compatible providers

---------

Co-authored-by: MrSubidubi <dev@bahn.sh>
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>

Cargo.lock

@@ -231,6 +231,7 @@ dependencies = [
  "jsonschema",
  "language",
  "language_model",
+ "language_models",
  "languages",
  "log",
  "lsp",
@@ -269,6 +270,7 @@ dependencies = [
  "time_format",
  "tree-sitter-md",
  "ui",
+ "ui_input",
  "unindent",
  "urlencoding",
  "util",
@@ -9097,11 +9099,11 @@ dependencies = [
  "client",
  "collections",
  "component",
+ "convert_case 0.8.0",
  "copilot",
  "credentials_provider",
  "deepseek",
  "editor",
- "fs",
  "futures 0.3.31",
  "google_ai",
  "gpui",