ui: replace stupid react-split-pane with allotment

.yarn/patches/react-split-pane-npm-0.1.92-93dbf51dff.patch

@@ -1,12 +0,0 @@
-diff --git a/index.d.ts b/index.d.ts
-index d116f54d6da12d24b48e24ff3636c9066059aa58..9d62eac28d5480aa6c2e796d603757d5999ea0af 100644
---- a/index.d.ts
-+++ b/index.d.ts
-@@ -25,6 +25,7 @@ export type SplitPaneProps = {
-   pane2Style?: React.CSSProperties;
-   resizerClassName?: string;
-   step?: number;
-+  children: React.ReactNode;
- };
- 
- export type SplitPaneState = {