Draft: Add program to migrate errortracking data from self-hosted instance to cloud instance

Migration plan:

1. Create a user on cloud instance that have insert capabilities on the selected table.
2. Determine the range for the data that needs will be migrated.
3. Create a temporary table that will hold the migrated data from self-hosting instances.
4. Execute the inserts from our self-hosted instances that push data to temporary table on cloud instances.
5. (Optional) - Drop temporary tables after inserts have been verified.

This is not intended to be merged but to be evaluated and gather feedback. As the migration is one-off, there is no point to keep this script in source.

Related to #2475 (closed)