Generate invite tokens from admin-fe

This MR allows to create invite tokens, list them on a separate tab, invite users via email. It also updates error handling and allows to generate tokens for resetting password.

Closes #28 (closed)

src/api/__mocks__/invites.js

+let inviteTokens = [
+  { expires_at: '01-01-2020', id: 1, invite_type: 'one_time', max_use: 3, token: 'DCN8XyTsVEuz9_KuxPlkbH1RgMsMHepwmZE2gyX07Jw=', used: false, uses: 1 },
+  { expires_at: '02-02-2020', id: 2, invite_type: 'one_time', max_use: 1, token: 'KnJTHNedj2Mh14ckx06t-VfOuFL8oNA0nVAK1HLeLf4=', used: true, uses: 1 },
+  { expires_at: '03-03-2020', id: 3, invite_type: 'one_time', max_use: 5, token: 'P6F5ayP-rAMbxtmtGJwFJcd7Yk_D2g6UZRfh8EskRUc=', used: false, uses: 0 }
+]
+
+export async function generateInviteToken(max_use, expires_at, authHost, token) {
+  const newToken = {
+    expires_at: '2019-04-10',
+    id: 4,
+    invite_type: 'one_time',
+    max_use: 3,
+    token: 'JYl0SjXW8t-t-pLSZBnZLf6PwjCW-qy6Dq70jfUOuqk=',
+    used: false,
+    uses: 0
+  }
+  inviteTokens = [...inviteTokens, newToken]
+  return Promise.resolve({ data: newToken })
+}
+
+export async function inviteViaEmail(email, name, authHost, token) {
+  return Promise.resolve()
+}
+
+export async function listInviteTokens(authHost, token) {
+  return Promise.resolve({ data: {
+    invites: inviteTokens
+  }})
+}
+
+export async function revokeToken(tokenToRevoke, authHost, token) {
+  inviteTokens.splice(3, 1, { ...inviteTokens[3], used: true })
+  return Promise.resolve()
+}
+