[admin] added form to upload kpis and the table to pick which kpi to import
[admin, error, page] added default error page
[error, page] upgrade to display stacktrace
[admin] kpi zip read page
[kpi] add unit test for stacktrace print
[kpi, import] added automatic import after uploading, unit test
[kpi-import] internationalization
[kpi-import] internationalization