Table improvements (#6958)

* Header toggling, resizable columns

* Allow all blocks in table cells, disable column resizing in read-only

* Fixed dynamic scroll shadows

* Refactor, scroll styling

* fix scrolling, tweaks

* fix: Table layout lost on sort

* fix: Caching of grip decorators

* refactor

* stash

* fix first render shadows

* stash

* First add column grip, styles

* Just add column/row click handlers left

* fix: isTableSelected for single cell table

* Refactor mousedown handlers

* fix: 'Add row before' command missing on first row

* fix overflow on rhs

* fix: Error clicking column grip when menu is open

* Hide table controls when printing

* Restore table header background

* fix: Header behavior when adding columns and rows at the edges

* Tweak header styling

* fix: Serialize and parsing of column attributes when copy/pasting
fix: Column width is lost when changing column alignment

shared/i18n/locales/en_US/translation.json

@@ -352,11 +352,14 @@
   "Replace": "Replace",
   "Replace all": "Replace all",
   "Profile picture": "Profile picture",
-  "Insert after": "Insert after",
-  "Insert before": "Insert before",
+  "Add column after": "Add column after",
+  "Add column before": "Add column before",
+  "Add row after": "Add row after",
+  "Add row before": "Add row before",
   "Align center": "Align center",
   "Align left": "Align left",
   "Align right": "Align right",
+  "Default width": "Default width",
   "Full width": "Full width",
   "Bulleted list": "Bulleted list",
   "Todo list": "Task list",
@@ -410,6 +413,7 @@
   "Sort ascending": "Sort ascending",
   "Sort descending": "Sort descending",
   "Table": "Table",
+  "Toggle header": "Toggle header",
   "Math inline (LaTeX)": "Math inline (LaTeX)",
   "Math block (LaTeX)": "Math block (LaTeX)",
   "Tip": "Tip",