Add Utilities page and timelock multisig

[sven-hash]

Add new Utilities section with tools for working with Alephium data

Why is this useful?

These utilities help developers and users quickly decode and convert Alephium-specific data without writing code or using the SDK directly. For example:

Paste an address to instantly see its group, type (asset/contract), and extract the contract ID
Convert between contract IDs and addresses
Validate and decode Base58/hex strings
Convert between human-readable ALPH amounts and atto-ALPH
Get block chain index from a block hash

• Add new Utilities section with tools for working with Alephium data
• Address utilities: address info, contract/token ID conversions, public key to address, sub-contract ID
• Encoding utilities: hex/string conversion, Base58 validation
• Amount utilities: ALPH/atto conversions, token amount formatting
• Block utilities: block chain index, target/difficulty conversions

[sven-hash]

Support timelock for multisig, related to #11

[polarker]

@sven-hash The deployment CI is waiting forever, I don't know why.