fix: improve curl transform accuracy

[jackkav]

todo

• ensure errors are visible for live validate, import modal and clipboard
• fix url-encoded form input
• replace old logic with curlconverter
• work on a parser which converts accurately back to existing request objects
• ensure inso cli can play nice with the wasm modules included in the browser version

Previous implementation coud handle a few cases curlconverter cannot and will result in an error

--d (single-dash long flag) │ curlconverter throws on --d (not valid curl), returns null                                                    --data-raw '@filename' │ curlconverter doesn't distinguish --data-raw from -d, treats @ as file ref (missing value) 
--data-urlencode 'key@filename' │ curlconverter resolves to key=@filename string instead of preserving file semantics 
--data-urlencode ' ' │ curlconverter URL-encodes space as +, our converter decodes but gets + not                                    -d 'key=value' (no Content-Type header) │ curlconverter auto-adds Content-Type: application/x-www-form-urlencoded, so it becomes params instead of text 

closes INS-1531