Finished adding basic category adding functionality

OpenArchival.Database/Category/ICategoryProvider.cs

@@ -0,0 +1,18 @@
+namespace OpenArchival.Database.Category;
+
+public interface ICategoryProvider
+{
+    public Task<Category?> GetCategoryAsync(string categoryName);
+
+    public Task<int?> GetCategoryId(string categoryName);
+
+    public Task<int> InsertCategoryAsync(Category category);
+
+    public Task<int> UpdateCategoryAsync(string categoryName, Category category);
+
+    public Task<IEnumerable<Category>> AllCategories();
+
+    public Task<int> InsertCategoryFieldOptionAsync(CategoryFieldOption option);
+
+    public Task<IEnumerable<CategoryFieldOption>> GetCategoryFieldOptionsAsync(int categoryId, int fieldNumber);
+}