908 account recovery ability to add contacts to trusted contacts list for account recovery

Closes dashboard#908

javascript/src/utilities/secrets.js

+import { secrets } from "secrets.js-grempe";
+import { encryptMessage } from "./signingUtilities.js";
+
+export /**
+ * Function generates a random bits length string, and output it in hexadecimal format
+ *
+ * @param {number} bits
+ */
+const generateRecoveryKey = bits => secrets.random(bits);
+
+/**
+ * Divide a secret expressed in hexadecimal form into numShares number of shares, requiring that threshold number of shares be present for reconstructing the secret
+ *
+ * @param {string} secret
+ * @param {number} numShares
+ * @param {number} threshold
+ * @param {number} [padLength=128]
+ */
+export const divideSecretToShares = (
+  secret,
+  numShares,
+  threshold,
+  padLength = 128
+) => secrets.share(secret, numShares, threshold, padLength);
+
+/**
+ * Reconstructs a secret from shares
+ *
+ * @param {array} shares
+ */
+export const combineSecret = shares => secrets.combine(shares);
+
+export const encryptShare = (share, publicKey) =>
+  encryptMessage(share, publicKey, "secretPart");