Revert "feat!: remove features related to the old thread page view"

This reverts commit 879d44aef99524c84719d91c628e772fba9335cb.

Reason for revert: It turns out the old reply editor can still be used
in the new thread page view by pressing the "R" key, and this can/will
make the CC communicate with the draft endpoints to save/retrieve
information.

Apart from this, some PEs were using the "old thread page" option as
well, even if it doesn't load all replies.

Finally, this revert also contains some changes to the modifications to
the data startup object so they work correctly (since now we have to use
StartupDataStorage, otherwise changes might not be saved).

Bug: twpowertools:124
Change-Id: Ie8153b9c8ef150b2417cb19b73bde0a5593876e2
diff --git a/src/static/_locales/en/messages.json b/src/static/_locales/en/messages.json
index 27c732c..4c655f7 100644
--- a/src/static/_locales/en/messages.json
+++ b/src/static/_locales/en/messages.json
@@ -63,6 +63,10 @@
     "message": "Redirect all threads opened in TW to the Community Console.",
     "description": "Feature checkbox in the options page"
   },
+  "options_loaddrafts": {
+    "message": "Activate the <code class=\"help\" title=\"This flag allows the Community Console to load a previously autosaved reply when loading a thread and clicking the reply button.\">enableLoadingDraftMessages<\/code> Community Console flag.",
+    "description": "Feature checkbox in the options page"
+  },
   "options_experimental_label": {
     "message": "(experimental)",
     "description": "Label which is placed next to an option to indicate that it may not work well or may break at any time"
@@ -135,6 +139,10 @@
     "message": "Show the number of questions and replies written by the OP within the last <span id='profileindicatoralt_months--container'></span> months next to their username.",
     "description": "Feature checkbox in the options page"
   },
+  "options_blockdrafts": {
+    "message": "Block the sending of your replies as you type to Google servers in the Community Console.",
+    "description": "Feature checkbox in the options page"
+  },
   "options_workflows": {
     "message": "Enable the workflows feature.",
     "description": "Feature checkbox in the options page"
@@ -151,6 +159,18 @@
     "message": "Show per-forum activity in profiles.",
     "description": "Feature checkbox in the options page"
   },
+  "options_interopthreadpage": {
+    "message": "Show <span id='interopthreadpage_mode--container'></span> in the Community Console.",
+    "description": "Feature checkbox in the options page. \"<span id='interopthreadpage_mode--container'></span>\" will be substituted with a selector which allows users to select whether they want the new thread page design or the old one."
+  },
+  "options_interopthreadpage_mode_previous": {
+    "message": "the old thread page design",
+    "description": "Select option added in #interopthreadpage_mode--container, in the options_interopthreadpage string"
+  },
+  "options_interopthreadpage_mode_next": {
+    "message": "the new thread page design",
+    "description": "Select option added in #interopthreadpage_mode--container, in the options_interopthreadpage string"
+  },
   "options_uispacing": {
     "message": "Reduce the whitespace in the Community Console and TW.",
     "description": "Feature checkbox in the options page"