Process IO and unknown errors

[ForNeVeR]

Currently, if any error happens during issue creation, nothing will happen. The Create Issue button will unblock and the user will be able to try again, but that's it. Nothing else (well, aside from the exception being logged to the error log).

Instead, let's handle errors during issue creation:

• for IO (or HTTP) errors, show a corresponding notification and suggest the user to try again;
• for other errors, tell the user to check the IDE log file and report an issue.

See the code near this line:

Todosaurus/src/main/kotlin/me/fornever/todosaurus/views/CreateIssueDialog.kt

Line 107 in 10e326b

// TODO: Process IO and unknown errors

Also, look for the number of this issue in the project code base.