Hardcode metadata anchor for DRep registration

[MSzalowski]

User Story
As a beta tester of govtool

I want to be able to register as a DRep without providing a metadata anchor

So I can save time.

Acceptance Criteria
Given that I am on the page during the DRep registration journey where a metadata anchor can be added

When I do not add a metadata anchor and press the "skip" button

Then when GovTool creates my registration transaction it will include the following anchor:
url: https://raw.githubusercontent.com/Thomas-Upfield/test-metadata/main/placeholder.json
hash: 654e483feefc4d208ea02637a981a2046e17c73c09583e9dd0c84c25dab42749

Definition of Done
When a person registering as a DRep skips the part where they should enter a metadata anchor then GovTool will create an anchor behind the scenes and attach it to their registration transaction.

[SandraRodziewicz]

Checked that I am able to register as a DRep skipping the metadata anchor page
Ready for stage