Refactoring Sygma docs

[haochizzle]

refactor:

• [x] larger restructure for docs to add sections for devs, for users, for cross-chain apps, relayers etc.
• [x] add tailored security documentation
• [ ] add relevant details for how relayers work under spectre vs zipline verification
• [x] add documentation for tailored security - selection mechanism
• [ ] add documentation for btc
• [ ] add documentation for cross-chain app multichain-deploy
• [x] add documentation for widget
• [ ] add documentation for validator-app

chores:

• [x] update github repositories to include new repos
• [x] update audits page to include veridise report
• [x] update FAQs to include tailored security resources
• [x] update examples to use cronos testnet where applicable
• [x] update video resources to include new substrate workshop
• [x] remove testnet faucet links (e.g. resources->official links page)
• [x] update glossary to include terms related to tailored security
• [x] update dictionary

closes:[#134][#142]