feat: add country/region select (#207)

Signed-off-by: sh1luo <690898835@qq.com>

web/src/SignupTable.js

@@ -73,6 +73,7 @@ class SignupTable extends React.Component {
             {id: 'ID', name: 'ID'},
             {id: 'Display name', name: 'Display name'},
             {id: 'Affiliation', name: 'Affiliation'},
+            {id: 'Country/Region', name: 'Country/Region'},
             {id: 'Email', name: 'Email'},
             {id: 'Password', name: 'Password'},
             {id: 'Confirm password', name: 'Confirm password'},