Store ModList filter states in redux

So that navigating between cells and back from other pages will persist the filters.

slices/modListFilters.ts

@@ -0,0 +1,59 @@
+import { createSlice, PayloadAction } from "@reduxjs/toolkit"
+
+import type { AppState, AppThunk } from "../lib/store"
+import type { Mod } from '../components/CellData';
+
+export type ModWithCounts = Mod & {
+  total_downloads: number;
+  unique_downloads: number;
+  views: number;
+  exterior_cells_edited: number;
+};
+
+export type ModListFiltersState = {
+  sortBy: keyof ModWithCounts,
+  sortAsc: boolean,
+  filter?: string,
+  category: string,
+  includeTranslations: boolean,
+}
+
+const initialState: ModListFiltersState = {
+  sortBy: "unique_downloads",
+  sortAsc: false,
+  filter: undefined,
+  category: "All",
+  includeTranslations: true,
+};
+
+export const modListFiltersSlice = createSlice({
+  name: "modListFilters",
+  initialState,
+  reducers: {
+    setSortBy: (state, action: PayloadAction<keyof ModWithCounts>) => ({
+      ...state,
+      sortBy: action.payload,
+    }),
+    setSortAsc: (state, action: PayloadAction<boolean>) => ({
+      ...state,
+      sortAsc: action.payload,
+    }),
+    setFilter: (state, action: PayloadAction<string | undefined>) => ({
+      ...state,
+      filter: action.payload,
+    }),
+    setCategory: (state, action: PayloadAction<string>) => ({
+      ...state,
+      category: action.payload,
+    }),
+    setIncludeTranslations: (state, action: PayloadAction<boolean>) => ({
+      ...state,
+      includeTranslations: action.payload,
+    }),
+    clearFilters: () => initialState,
+  },
+})
+
+export const { setSortBy, setSortAsc, setFilter, setCategory, setIncludeTranslations, clearFilters } = modListFiltersSlice.actions
+
+export default modListFiltersSlice.reducer