Add images without backend

[kan-ish]

The library should have a method for uploading images without sending the images to a backend, should the user need it. I have implemented a solution to this with the following code for the uploadByFile function provided by the libary -

async uploadByFile(file) {
	const response = await uploadFile(file);
	if (response.success) {
		return {
			success: 1,
			file: {
				url: response.file,
			},
		};
	}
}

async function uploadFile(file) {
	return new Promise((resolve, reject) => {
		const reader = new FileReader();
		reader.onload = function (e) {
			const base64URL = e.target.result;
			resolve({ success: 1, file: base64URL });
		};

		reader.onerror = function (error) {
			reject(error);
		};

		reader.readAsDataURL(file);
	});
}

The user can then store the saved editor data (obtained from editor.save()) as-it-is in the backend as an object or even a single string, without the images being stored elsewhere. Some users might need this, as did I.