When testing plugin manager with real downloads, it could happen that the test run forever. Fortunately, test suite will be interrupted after 20 minutes, but it could be useful not to fail the whole test suite but only warn in that case.
By default, plugin manager still wait indefinitely but it can be modified using new `--timeout` option:
```sh
bin/plugin --install elasticsearch/kibana --timeout 30s
bin/plugin --install elasticsearch/kibana --timeout 1h
```
Closes#4603.
Closes#4600.
Now with have proper exit codes for elasticsearch plugin manager (see #3463), we can add a silent mode to plugin manager.
```sh
bin/plugin --install karmi/elasticsearch-paramedic --silent
```
Closes#3628.
When installing a plugin, we use:
```sh
bin/plugin --install groupid/artifactid/version
```
But when removing the plugin, we only support:
```sh
bin/plugin --remove dirname
```
where `dirname` is the directory name of the plugin under `/plugins` dir.
Closes#3421.
David Pilato
Jun Ohtani
Clinton Gormley
Lee Hinman