feat: Add file based ResourceStore (#52)

* feat: Add file resource store

* test: Write some tests for FileResourceStore

* fix: Reformat code and fix various small things from reviews

* fix: Change constants to just be the corresponding URL

* fix: Remove extra unnecessary wrap in a Promise

* fix: Write some more tests and fix related bugs

* fix: Use old way to import fs promises to support older Node versions

* refactor: Refactor code and tests

* refactor: Refactor and better document code

* fix: Change comparison with undefined by typeof check

* fix: Invert typeof check

src/ldp/representation/RepresentationMetadata.ts

@@ -12,9 +12,9 @@ export interface RepresentationMetadata {
    */
   raw: Quad[];
   /**
-   * The metadata profiles.
+   * Optional metadata profiles.
    */
-  profiles: string[];
+  profiles?: string[];
   /**
    * Optional size of the representation.
    */
@@ -35,4 +35,13 @@ export interface RepresentationMetadata {
    * Optional timestamp of the representation.
    */
   dateTime?: Date;
+  /**
+   * Optional link relationships of the representation.
+   */
+  linkRel?: { [id: string]: Set<string> };
+  /**
+   * Optional slug of the representation.
+   * Used to suggest the URI for the resource created.
+   */
+  slug?: string;
 }