Qgis-plugin-manager

* Order the plugin list by folder name
* Show file permissions warning if there are more than 2 different values

* Display `PYTHONPATH` when QGIS library is not found
* Display tip to restart QGIS Server after a plugin installation

* Better warning when we are not in the correct directory without any plugin
* Better warning when the user can not extract the ZIP in the folder

* Add a `search` command to search plugins among tags and names
* Add an `upgrade` command to upgrade all plugins installed
* Add an example with a plugin having a space in its name
* Add some information about the user and file permissions when showing plugins
* Display plugin name similarity when installing if the given name is not found
* Display a better error message if the folder/file can not be removed

* Fix a Python error when not the encoding was not set when opening files

* Adds some colors in the terminal
* Better management of QGIS upgrade when the version was hardcoded in the `sources.list` file
* Fix an issue about version name
* Refactoring the code