Add basic support for AnkiConnect (WIP)

[MarkoSagadin]

This is a prototype implementation.

In the current state the md2anki will:

• Send processed cards to the Anki via 'addNote' API
• Send images to the Anki via 'storeMediaFile' API
• Display basic info when that is being done
• Display error messages if any step fails

This feature is far from done:

• deck name and note type are currently hardcoded, they should be provided by the caller for each card/note.
• error handling and validation are missing.
• code style will probably need to be adjusted.

There are several TODO comments that ask questions.

Related: #3