[Enhancement] Support Importing N:N tables by Associate and Disassociate Requests

[LinnZawWin]

Based on Issue #8, it seems like the previous filtering of the N:N tables is removed.

However, the table is in grey colour (probably because it does not support import) and all the attributes of the table are marked as "Invalid Attributes" and only visible when the "Hide Invalid Attributes" is unchecked.

It is understood that the CUD operations are not supported for those N:N tables as mentioned in Issue #8 but it would be great if the tool would allow importing the exported data by Associate and Disassociate requests.
Currently, only the following error message is present when I attempt to import the data to N:N table.