credentials: file authoring/editing language support

[justinmk3]

As a user, when editing ~/.aws/* credentials files such as ~/.aws/credentials or ~/.aws/config, I want syntax support for AWS credentials files:

• MVP
  • Auto-completion
  • Syntax highlight
  • Syntax check / errors
• Future (LSP based?)
  • File outline
  • Go to Definition
  • Find References
  • Smart rename

Notes

• Sections can have subkeys! (ref)
  • Introduced in 2014 for s3: https://docs.aws.amazon.com/cli/latest/topic/s3-config.html
  • Example:

    [profile development]
    aws_access_key_id=foo
    aws_secret_access_key=bar
    s3 =
      max_concurrent_requests = 20
      max_queue_size = 10000
      multipart_threshold = 64MB
    

[justinmk3]

"ini" syntax highlighting: #2780