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/lightbox/ImageViewing/components/ImageItem/ImageItem.android.tsx

@@ -315,7 +315,6 @@ const ImageItem = ({
       <GestureDetector gesture={composedGesture}>
         <AnimatedImage
           contentFit="contain"
-          // NOTE: Don't pass imageSrc={imageSrc} or MobX will break.
           source={{uri: imageSrc.uri}}
           style={[styles.image, animatedStyle]}
           accessibilityLabel={imageSrc.alt}

src/view/com/lightbox/ImageViewing/components/ImageItem/ImageItem.ios.tsx

@@ -139,7 +139,6 @@ const ImageItem = ({imageSrc, onTap, onZoom, onRequestClose}: Props) => {
         {(!loaded || !imageDimensions) && <ImageLoading />}
         <AnimatedImage
           contentFit="contain"
-          // NOTE: Don't pass imageSrc={imageSrc} or MobX will break.
           source={{uri: imageSrc.uri}}
           style={[styles.image, animatedStyle]}
           accessibilityLabel={imageSrc.alt}