Custom ESLint rules to enforce new ThemedComponent selector convention

The following cases are covered:
- ThemedComponent wrapper selectors must not start with ds-themed-
- Base component selectors must start with ds-base-
- Themed component selectors must start with ds-themed-
- The ThemedComponent wrapper must always be used in HTML
- The ThemedComponent wrapper must be used in TypeScript _where appropriate_:
  - Required
    - Explicit usages (e.g. modal instantiation, routing modules, ...)
    - By.css selector queries (in order to align with the HTML rule)
  - Unchecked
    - Non-routing modules (to ensure the components can be declared)
    - ViewChild hooks (since they need to attach to the underlying component)

All rules work with --fix to automatically migrate to the new convention
This covers most of the codebase, but minor manual adjustment are needed afterwards

lint/src/util/misc.ts

@@ -0,0 +1,42 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+
+export function stringLiteral(value: string): string {
+  return `'${value}'`;
+}
+
+export function match(rangeA: number[], rangeB: number[]) {
+  return rangeA[0] === rangeB[0] && rangeA[1] === rangeB[1];
+}
+
+export function findUsages(context: any, localNode: any): any[] {
+  const ast = context.getSourceCode().ast;
+
+  const usages: any[] = [];
+
+  for (const token of ast.tokens) {
+    if (token.type === 'Identifier' && token.value === localNode.name && !match(token.range, localNode.range)) {
+      usages.push(context.getSourceCode().getNodeByRangeIndex(token.range[0]));
+    }
+  }
+
+  return usages;
+}
+
+
+export function isPartOfTypeExpression(node: any): boolean {
+  return node.parent.type.startsWith('TSType');
+}
+
+export function isClassDeclaration(node: any): boolean {
+  return node.parent.type === 'ClassDeclaration';
+}
+
+export function isPartOfViewChild(node: any): boolean {
+  return node.parent?.callee?.name === 'ViewChild';
+}