FP Registry Improvements

[RafilxTenfen]

• Make security contact mandatory in guide and CI check
• After signing the transaction you should have it in hex format. some people missed the signing part because the relevant instructions are in the other page. It would be good if we stress the tx hex should be signed (we have a placeholder tx hex in the upper example which is not signed, which is confusing)
• curl https://bitcoin-testnet-archive.allthatnode.com/ this website is not stable and people often get curl: (6) Could not resolve host: bitcoin-testnet-archive.allthatnode.com. Maybe we can choose another one that is stable? And, people also got confused about performing this step event after the successfully submitted their tx via bitcoin-cli sendrawtransaction. So, it’s better to stress that we recommend submitting the signed tx by running bitcoind node locally and using bitcoin-cli sendrawtransaction to submit tx. For those they don’t want to run a bitcoind node they can choose a third part endpoint but it requires trust and they can be not stable
• when creating finality provider information object, it is confused to have "btc_pk": "<eots_btc_pk>", many people thought this is the staker pk because we use --finality-provider-pk=<fp_pk> in the other place. So it would be less confusing if we make it consistent (eg "finality_provider_pk"=<finality_provider_eots_pk>)
• if user has installed the staker-cli v0.2.0, then ./bbn-test-4/finality-providers/scripts/fp-check-tx.sh would fail as staker-cli 0.2.0 does not support the min-staking-amout flag in staker-cli transactions check-phase1-staking-transaction. So better to make a new release of staker-cli and ask user to use the correct version.