Feature: new "report a bug" modal (#13530)

* WIP: report a bug api/ui

* fix lint

* add USER_USERNAME

* extend sendTxn tests / checks + fix bug report email

* fix lint

* add more checks to sendTxn - fix bug-report variables

* fix lint / ci

* fix test: reset email config url

* fix test stub

* fix tests

* refactor the variables checks

* lint.

* move bug-report page as a modal

* send user_email to the email

* show true/false instead 1/0

* fix issues

* fix footer report bug email if not logged in

* fix styles/margins

* prefill user's email

* show facebook email if local email not existing

* bugReportSuccessModal.vue

* add BROWSER_UA to mail properties

* extract bugReportLogic to its own lib file for unit test

* test api validators

* fix lint

website/client/src/components/header/menu.vue

@@ -311,7 +311,7 @@
               </router-link>
               <a
                 class="topbar-dropdown-item dropdown-item"
-                :href="bugReportMailto"
+                @click.prevent="openBugReportModal()"
                 target="_blank"
               >
                 {{ $t('reportBug') }}