Downloading files/folders as an archive using bulk actions

### Background
Currently, via GUI users can download files from storages/FS mounts one by one. Folders couldn't be downloaded at all. It would be more convenient for the user to have the ability to select a bunch of files/folders and download them as an archive to his local machine.

### Approach
When user selects some files/folders in the storage, the Download button shall appear. If the user clicks it - the modal window with 2 options appears: download as `tar.gz` archive and download as `zip` archive. User chooses format, then the generated archive with the selected objects shall be automatically downloaded to the local machine.

- user can download selected items in any of the proposed archive formats
- user can download files/folders only if the summary size of selected objects does not exceed specified in the system
- admins can configure the max downloading size by system preferences - for all system in general (`global size`) and for each region separately (`region size`)
- if the `region size` value is not set, the system shall use the `global size` value
- if the summary size of selected objects exceeds the max downloading size, the system shall notify the user and shall not generate the archive
- this feature shall be available for both - Object Storages and FS mounts