test: renamed auto to unit

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugin: improve tst_PluginDependencyGraphBuilder code

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugin: add more test for PluginDependencyGraphBuilder

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugin: improve tst_PluginDependencyGraphBuilder code

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugin: PluginState documentation updated

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugin: add documentation for PluginStateService

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugin: add documentation and tests for PluginStateService

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugin: add documentation for PluginStateStorage09

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>