Remove deprecated models and mobx usage (react-query refactor) (#1934)

* Update login page to use service query

* Update modal to use session instead of store

* Move image sizes cache off store

* Update settings to no longer use store

* Update link-meta fetch to use agent instead of rootstore

* Remove deprecated resolveName()

* Delete deprecated link-metas cache

* Delete deprecated posts cache

* Delete all remaining mobx models, including the root store

* Strip out unused mobx observer wrappers

src/view/com/auth/create/Policies.tsx

@@ -4,12 +4,14 @@ import {
   FontAwesomeIcon,
   FontAwesomeIconStyle,
 } from '@fortawesome/react-native-fontawesome'
+import {ComAtprotoServerDescribeServer} from '@atproto/api'
 import {TextLink} from '../../util/Link'
 import {Text} from '../../util/text/Text'
 import {s, colors} from 'lib/styles'
-import {ServiceDescription} from 'state/models/session'
 import {usePalette} from 'lib/hooks/usePalette'
 
+type ServiceDescription = ComAtprotoServerDescribeServer.OutputSchema
+
 export const Policies = ({
   serviceDescription,
   needsGuardian,