[REF] mass_mailing: convert templates to themes and clean code

* Remove mass mailing template switching system (lemon, airmail, ...)
and replace it with a theme selector which only toggle a different
class on the body.
* Lint JS files.
* Change the way the editor is overridden by mass_mailing in a more
odoo way (put the JS in assets and check on runtime if it must be
applied.

+ fix editor style
+ remove useless code
+ remove odoo template

1 files changed, 17 insertions, 0 deletions

diff --git a/addons/mass_mailing/static/src/less/mass_mailing.ui.less b/addons/mass_mailing/static/src/less/mass_mailing.ui.less
new file mode 100644
index 00000000000..9b72a72adc7
--- /dev/null
+++ b/addons/mass_mailing/static/src/less/mass_mailing.ui.less
@@ -0,0 +1,17 @@
+.o_mail_theme_selector {
+    > a {
+        .o-position-absolute(6px, 6px);
+    }
+
+    .dropdown-menu {
+        .o-position-absolute(@odoo-navbar-height - 1, -1px, -1px, -1px);
+        margin: 0;
+        border-radius: 0;
+        overflow: auto;
+        background-color: @o-we-color-dark;
+
+        > li:hover > a {
+            background-color: @o-we-color-darker;
+        }
+    }
+}