[Text import] Add support for tabs as a separator in text import

{"ops":[{"insert":"I just imported my deck from an .ods sheet to Archidekt, and ran into an issue importing it as text. Copying text multiple multuple columns of data includes the separator character, which tends to be a tab, instead of a single whitespace.\n\nCould the text import tool be improved so that it also supports tabs as a separator.\n\nThank you! :)\n"}]}