feat(neovim): upgrade kickstart neovim configuration (#128)

Besides upgrading `kickstart` configuration, the following changes were made:

* add `avante` to start working with `AI` code generation and reduce code boilerplate creation
* configure ide image/container with environment variables:
  * `NVIM_GIT_USER_EMAIL`: email associated with git commit
  * `NVIM_GIT_USER_NAME`: name associated with git commit
  * `NVIM_ANTHROPIC_API_KEY`: `anthropic` api key, used by `avante`
  * `NVIM_GH_TOKEN`: `github` token, used by `github cli`

Reviewed-on: #128
Co-authored-by: Joao P Dubas <joao.dubas+gitea@gmail.com>
Co-committed-by: Joao P Dubas <joao.dubas+gitea@gmail.com>

docker-compose.yml

@@ -1,13 +1,20 @@
 ---
 services:
   nvim:
-    build: .
+    build:
+      context: .
+      args:
+        GIT_USER_EMAIL: ${NVIM_GIT_USER_EMAIL:-nobody@example.com}
+        GIT_USER_NAME: ${NVIM_GIT_USER_NAME:-noboby}
     image: 'joaodubas/nvim:${NVIM_TAG:-latest}'
     init: true
     restart: unless-stopped
     hostname: local
     entrypoint: sleep
     command: infinity
+    environment:
+      ANTHROPIC_API_KEY: ${NVIM_ANTHROPIC_API_KEY:-no-api}
+      GH_TOKEN: ${NVIM_GH_TOKEN:-no-token}
     volumes:
       - './config/atuin:/home/coder/.config/atuin'
       - './config/git:/home/coder/.config/git'