Revert partial definition concept

[corverroos]

Problem to be solved

We introduced the concept of "partial cluster definition", as part of #1490 and #1520. This was however incorrect.

The solo flow usecase is as follows:

• Solo operator performs the solo flow on the launchpad
• They only populate the creator field, both address and config_signature
• They do not populate the operator fields, no addresses or config_signatures nor enrs or enr_signatures.
• They get a link to the generated "(partial) definition" they just created
• They use that link in the charon create cluster command to create a p2p keys and validator key shares and the lock file. See cmd: add --definition-file flag to create cluster command #1558 for the first attempt.

The problem with the first attempt was that the lock file creator.config_signature must remain valid.

• The current Go logic uses N empty operator addresses to calculate the config hash (since the there are N operator structs containing only enr fields).
• But the partial cluster definition require empty operator array, which isn't the case after the enrs have been added.
• We do not want to add switching logic to detect some "special" case where it will use an empty operator slice when calculating the config hash (like was originally suggested).

Proposed solution

So the suggestion is to scrap the concept of a "partial definition" and instead:

• The launchpad create a normal solo flow cluster definition.
• The requirement is that all operator fields are empty strings, so N operators with empty string address, enr, config_signature, and enr_signature fields (note not an empty operator array, but empty operator json objects, [{},{},{}] vs [].
• The resulting config_hash should therefore use N empty string operator addresses.
• The definition_hash can also be populated as normal, it will be overwritten by the create cluster command.

The charon create cluster will then do the following:

• download the --definition-file from the url.
• verify the hash and signatures it like any normal definition file.
• adhoc verify that operators are empty structs.
• Populate the operator enrs
• Recalculate the definition_hash
• Use that definition as is when creating the lock file.
• The config_hash and operator config_signature therefore remains valid.

Out of Scope

If there is anything to highlight as out of scope for this issue, please outline it here.