Bump version to 0.2.90

Real development starts now.
Include macros for package config
Include macro to generate export header for libraries
libhawaiicore: Rename to libhawaiishell and export targets

This is now a truly public library.

Issue: #122
libhawaiishell: Add some types

Issue: #122
libhawaiishell: Base view for the shell

Issue: #122
client: Say hello to DesktopView

BackgroundWindow now becomes DesktopView which will load the desktop
view from the current shell plugin.

Issue: #122
client: Say hello to PanelView

LauncherWindow becomes PanelView, a view for all panels that will load
the QML code from the current shell plugin.

Issue: #122
shells: Say hello to the desktop shell

Add some boilerplate for the desktop shell plugin.
There's nothing much in here yet, soon some components will be moved
here from the client.

Issue: #122
libhawaiishell: Say hello to PluginMetadata

Simple class that reads plugin metadata.

Issue: #122
client: Rename resource file

desktop-shell.qrc is not a valid name anymore, better call it
client.qrc.

Issue: #122
client: Shell plugin loading mechanism

Add a shell manager that takes care of loading shell handlers.

Issue: #122
notifications: Separate notifications daemon from the shell client

This way notifications can be managed more easily making Hawaii more
modular.

Issue: #123
notifications: Cleanup

No functional changes.

Issue: #123
notifications: Switch license to GPL v2 or later

Seems better for an executable.

Issue: #123
notifications: Start daemon when wl_notification_daemon is registered

Listen to Wayland registry events and start the notifications daemon as
soon as wl_notification_daemon is registered.

Issue: #123
client: Shell user interface manager

ShellUi now manages desktop and panel views and handles screens.

Issue: #122
client: Remove ShellWindow

This was used as a generic window without wl_shell_surface but we now
have specific components that are about to be moved to a QML module so
it's time to clean things up a bit.

Issue: #124
hawaii.xml: Handle surface role with separate interfaces

Add a wl_hawaii_shell_surface interface with requests to set roles to
shell surfaces and handle popups with a dedicated interface called
wl_hawaii_popup_surface.

Issue: #124
components: Move window components to a QML plugin

Make components such as Dialog, Popup, Overlay etc... usuable by
external processes. To do so we move the code to a QML module.

Issue: #124