Improve AnalyzeExpense Support

[ThomasDelteil]

Currently there is limited support for AnalyzeExpense in Textractor. We support sync and async API calls.

However we need to implement the following:

• [x] Allow duplication of KV for summary fields, they are not unique and there can be multiple TOTAL fields for example
• [x] Add support for line items. Line items are typically stored in a tabular format and represent individual elements from a transaction
• [x] Add auto-complete and attribute support for each of the existing summary fields
• [x] Add visualization support for summary fields to distinguish them from the normal KV
• [x] Add a tutorial that shows the use of the analyze expense API