Vertical divider on service-based dialogs

This helps visually separate the left from right on these windows.
Introduce the templater dialog

This new dialog will be attached to the card layout screen and provide
the user with a way to build up an on-the-fly TTS tag and insert it into
their template layout.
Populate card fields in templater

This comes off of the card layout window's model reference.
Add controls for visibility and side

This is now presented as a grid of labels with three dropdowns: source
field, visibility, and template side.
Add templater_ configuration options

These will be usable for saving the state of the templater dialog
between sessions.
Add show() support to templater

This restores the last-used (or default) field for each of the three
dropdowns and then focuses the "field" dropdown.
Implement basic template insertion

This still needs support for the global style and encoding HTML
attributes, but is otherwise done.
Add global CSS hiding support to templater

This works by adding a CSS rule to the style box if it is not already
present.
Enable HTML attribute escaping

This shouldn't be an issue, but could be if a voice ever included an
ampersand or something similar.
Merge branch 'add/templater' into develop

Adds a new "Add TTS" button to the card layout window that allows the
user to build out a TTS tag for exactly the service options that they
want.