[Implementation] Create a import widget that imports all type of tabular data

[ColinFay]

We can use all the tools available in R to build a global importer for tabular format.

How it would work:

• The widget has a file selector
• File is read and previewed
• The user enters the cypher code
• The file is read as a csv in a temp file
• A plumber app is launched
• That api takes a path and generates a csv
• The widget generates a LOAD CSV FROM {plumberapiurl}cypher code
• The generated code is sent to the Neo4J instance