Add support for tracking the is_uploaded status in the results table (#312)

* Add support for tracking the is_uploaded status in the results table

* Add unit tests for measurement upload status

This implements: https://github.com/ooni/probe/issues/1457

* Update cmd/ooniprobe/internal/database/actions.go

Co-authored-by: Simone Basso <bassosimone@gmail.com>

cmd/ooniprobe/internal/database/migrations/3_results_is_uploaded.sql

@@ -0,0 +1,15 @@
+-- +migrate Down
+-- +migrate StatementBegin
+
+ALTER TABLE `results`
+DROP COLUMN result_is_uploaded;
+
+-- +migrate StatementEnd
+
+-- +migrate Up
+-- +migrate StatementBegin
+
+ALTER TABLE `results`
+ADD COLUMN result_is_uploaded TINYINT(1) DEFAULT 1 NOT NULL;
+
+-- +migrate StatementEnd