ClearTextPassword plugin: report error on empty password

The password is empty when it's not set in the settings file.
Settings: Hide unwanted elements on the OutgoingPage

As the page is disabled before it is saved we can not use isEnabled() to determine
whether to save the SMTP password or not. isVisible works fine though and the GUI
looks cleaner that way.

REVIEW: 118509
GUI: Prevent a blank line in the Outgoing settings page

It's better to sync the port warning state with whatever is initially in the
settings.

REVIEW: 118523
Gui: Only set default port when changing submission method

Setting the default port during the initial run of the SettingsDialog is already handled
by MSA::Account and setting it during updateWidgets causes the port to be reset when opening
the SettingsDialog.

Signed-off-by: Jan Kundrát <jkt@flaska.net>

Conflicts:
	src/Gui/SettingsDialog.cpp

REVIEW: 118528
Ubuntu:Add Click pkg manifests and change cmake to build click pkgs

Adds a new option UBUNTU_CLICK_MODE for use when either running
trojita on device from QtCreator or building click packages.
This option installs trojita to a contained location

REVIEW: 118429
Ubuntu: modify TrojitaVersion to configure version in manifest.json

Adds an CLICK_MODE option to TrojitaVersion.cmake which if true
will configure manifest.json on each build

REVIEW: 118429
Ubuntu: Remove QCommandLineParser options from src/Ubuntu/main.cpp

For some reason UbuntuTouch/Unity8 require --desktop_file_hint
and --stage_hint to be passed when launching an app. Which
the commandline parser was blocking these args. Since the
commandline options were only really just setting the size of
the qquickview we can safely just remove it and stick to a fixed
size window.

Removed associated context properties from main.qml

REVIEW: 118429
Ubuntu: Modify main.cpp to find main.qml in click package

With click packages the qml dir does not fall under a 'standard'
location. So it first looks for trojita.json in the root of the click
package, once that's found we can then descend to main.qml from
there.

REVIEW: 118429