Allow to specify format details when uploading TXT files in DwC importer

[LocoDelAssembly]

Due to problems with multi-line data, we have to change our TSV output format to have text with quotes (not for every text, only text that would otherwise break the dataset if not escaped/quoted correctly).

Required changes

Frontend

When tsv, txt or csv (new) is uploaded, before sending to backend the user should be asked about field delimiter and string delimiter. For field delimiter options are: Tab, Comma, Semicolon, Space and Other. When Other is selected a text box to supply a character must be available for the user to type it in. Only ONE option can be selected. For string delimiter options are ' and " and None (perhaps in italics or something else to differentiate from actual values).

Defaults for each format are these:

Format	Field delimiter	String delimiter
csv	Comma	"
tsv	Tab	"
txt	Tab	"

Backend

• [x] Receive params col_sep and quote_char filled with data from field delimiter and string delimiter respectively and pass them through Ruby's CSV reader.
• [x] Change download table to output with quote_char = '"' (Ruby's default) and col_sep = "\t".

[LocoDelAssembly]

Missing frontend functionality:

• Defaults are not being applied as per table above, options are always blank.
• When 'Other' is selected that is being sent literally instead of providing a text input to the user (with a text input on the left like LibreOffice?)
• csv still not allowed.

LibreOffice dialog: