Clarify XRPL EVM Sidechain as a standalone L1

[vriveraPeersyst]

Title: Clarify XRPL EVM Sidechain as a standalone L1

Description:
This update refreshes the XRPL EVM Sidechain documentation to improve clarity, navigation, and developer onboarding.

• New Content: Adds an IBC protocol overview with channel tables and explorer references.
• Information Architecture: Refactors bridge documentation into multiple optional pathways (Axelar, IBC, Wormhole) and consolidates cross-chain tutorials under a new Advanced Guides → Cross-Chain Transactions section.
• Developers: Reorganizes core EVM tutorials (develop → deploy → verify → interact), introduces clearer resources for building native dApps, and moves Goldsky and Oracle integrations into dedicated sections.
• Users: Consolidates introduction materials into a single “What is the XRPL EVM?” page, updates onboarding (MetaMask/Keplr, funding options like Squid, Skip, Gas.zip), and improves sidebar flow.
• Copy & Terminology: Clarifies chain positioning as a standalone L1 built on Cosmos SDK, using native XRP for gas, with Comet BFT and an independent POA governance.

These changes modernize the docs, highlight the standalone nature of the network, and streamline both native and cross-chain development paths.