Load settings from local.settings.json for add sql bindings quickpick (#16957)

* load settings from local.settings.json for add sql bindings quickpick

* cleanup

* addressing comments

extensions/sql-database-projects/src/common/parseJson.ts

@@ -0,0 +1,45 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.md in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+// copied from vscode-azurefunctions extension
+
+import * as jsonc from 'jsonc-parser';
+import * as constants from './constants';
+
+/**
+ * Parses and returns JSON
+ * Has extra logic to remove a BOM character if it exists and handle comments
+ */
+export function parseJson<T extends object>(data: string): T {
+	if (data.charCodeAt(0) === 0xFEFF) {
+		data = data.slice(1);
+	}
+
+	const errors: jsonc.ParseError[] = [];
+	const result: T = <T>jsonc.parse(data, errors, { allowTrailingComma: true });
+	if (errors.length > 0) {
+		const [line, column]: [number, number] = getLineAndColumnFromOffset(data, errors[0].offset);
+		throw new Error(constants.jsonParseError(jsonc.printParseErrorCode(errors[0].error), line, column));
+	} else {
+		return result;
+	}
+}
+
+export function getLineAndColumnFromOffset(data: string, offset: number): [number, number] {
+	const lines: string[] = data.split('\n');
+	let charCount: number = 0;
+	let lineCount: number = 0;
+	let column: number = 0;
+	for (const line of lines) {
+		lineCount += 1;
+		const lineLength: number = line.length + 1;
+		charCount += lineLength;
+		if (charCount >= offset) {
+			column = offset - (charCount - lineLength);
+			break;
+		}
+	}
+	return [lineCount, column];
+}