Fix commission rate data corruption

[ghost]

Purpose

Due to an earlier bug validators commissions rates wasn’t adjusted on chain parameter updates. This was fixed in PR
https://github.com/Concordium/concordium-scan/pull/136/files#

Corrupted data was however not fixed which is handled in this PR.

Error is now visible in the CCD scan on stagenet since we now compare the actual payday commission rates with the latest change received from the node.
https://github.com/Concordium/concordium-scan/pull/139/files
#143

In cases where the latest commission rate change was due to a chain update, the effect has never been updated in the database and indicators are wrongly shown.

Changes

• Add migration job flow to main import job
• Add migration job which updated commission rates
• Add generic metric for block height and added to main process such that we can observe if any job blocks import. Also migrated contract read height to this metric.
• Removed custom Source Class Name enricher and use the default from Serilog. The custom wasn’t printing classes with generics correctly.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.

[orhoj]

Going forward it would be nice to get a change like this split into two PR's:

1. A renaming refactoring PR. No functionality is affected, but all the interface changes etc. are made.
2. The actual migration script PR.

I know you might have determined the need for the refactoring while doing the migration, but the above would make it easier to review.