Integrate the new verification flow classes into server

[marcocastignoli]

After finishing #1821, #1822, #1823 we can proceed and update sourcify-server to use the new verification flow.

[marcocastignoli]

We have to decide what to do with the legacy verification functions in lib-sourcify.

There are two options:

1. Delete them and devs will not upgrade to lib-sourcify@2: the con I see with this is that then we'll have to maintain two different lib-sourcify if we find any bad bug for a long time.
2. Keep them in lib-sourcify@2: the con is that the library will contain legacy and not used code. But I don't think it's a huge problem. We can move them in a Legacy namespace marking them as deprecated and allowing an easy transition for developers.

@kuzdogan, @manuelwedler opinions?

[manuelwedler]

We decided to not upgrade legacy lib-sourcify for bugs and drop all old functions from new lib-sourcify.