Remove Kiln testnet configs

[Zachinquarantine]

Changes

Removes remaining configs for the deprecated "Kiln" testnet.

Types of changes

Removes JSON configs and various other configs.

What types of changes does your code introduce?

• Bugfix (a non-breaking change that fixes an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a fix or a feature that would cause existing functionality not to work as expected)
• Documentation update
• Code style update (formatting, renaming)
• Refactoring (no functional or API changes)
• Build-related changes
• Other: description

Testing

Requires testing

• Yes
• No

If yes, did you write tests?

• Yes
• No

[MarekM25]

I haven't removed it because it was used by Lodestar team in their CI. Let me confirm if they're still using it

[rubo]

@dapplion Do you guys still need this?

@Zachinquarantine In case of removal, could you please remove src/Nethermind/Chains/themerge_kiln_testvectors.json as well?

[dapplion]

CC: @g11tech, he built that CI you mention on Lodestar

[g11tech]

CC: @g11tech, he built that CI you mention on Lodestar

I don't think we use kiln configs but i will check and update what we use

[MarekM25]

Yes, I confirmed it with @g11tech before. Thx @Zachinquarantine for your PR :)