Delay app rendering till settings are loaded

[ygrishajev]

We use quite some tweaks to make sure we get our settings available. For instance all the chain data fetched via react query hooks depends on url got from settings. This causes checks in every such hook with weird logic. These hooks are used on every page and cause loading states anyway. So we need to make sure app doesn't load till we have all the data for the app to function properly.

Acceptance criteria:

• make sure the app rendering is delayed till settings are fetched
• app should be in the loading state meanwhile
• refactor settings to make sure interface guarantees required props presence
• remove settings values checks across the app