Add `get_total_size_on_disk` method to `RemoteData`

[GeigerJ2]

I added this while I was working on writing the code that warns the user about the possible large file size to be retrieved in PR #6578, but I think it warrants a separate PR.

The simplest way I found to obtain the whole file size of the directory associated with a RemoteData object was to use listdir_withattributes recursively. If somebody is aware of a better alternative, please feel free to comment.

Will add some tests shortly.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 82.60870% with 16 lines in your changes missing coverage. Please review.

Project coverage is 77.94%. Comparing base (c532b34) to head (9c3d2ba). Report is 39 commits behind head on main.

Files with missing lines	Patch %	Lines
src/aiida/orm/nodes/data/remote/base.py	88.24%	8 Missing :warning:
src/aiida/cmdline/commands/cmd_data/cmd_remote.py	50.00%	7 Missing :warning:
src/aiida/common/utils.py	90.00%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6584      +/-   ##
==========================================
+ Coverage   77.92%   77.94%   +0.02%     
==========================================
  Files         563      563              
  Lines       41671    41761      +90     
==========================================
+ Hits        32467    32545      +78     
- Misses       9204     9216      +12     

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[giovannipizzi]

This is maybe machine-dependent, but rather than going via our API (that is more robust, but definitely going to be slower, I think) have a first "fast" option just running du -s and parsing the output (but careful about units! E.g. it uses "blocks", on some systems it's 512 or 2048bytes!! And if it fails, fall back to your solution?

[GeigerJ2]

Note to self to run du via exec_command_wait method from transport.

[GeigerJ2]

Thanks for the review, @agoscinski! I'm currently still working on this, will ping you once it's again ready for review.

I think the output of du --apparent-size is the same as with lstat, so you do not need to use lstat

The reason I'm providing lstat as a fallback option is if du is not available (e.g., MacOS, as you mentioned, didn't know that ^^), or if exec_command_wait isn't available, which will be the case for FirecREST.

[GeigerJ2]

OK, this should be ready for a final review, @agoscinski and @khsrali. Also pinging, @mikibonacci, if you want to provide some feedback on the CLI/API for use in AiiDAlab?

[GeigerJ2]

Thanks again for the review, @khsrali, I implemented your proposed changes.

[GeigerJ2]

Thanks again for the review, @khsrali. I wrote down my reasoning for point 1 in my response to your comment in the code, and implemented point 2. Once CI passes here (hopefully), I'll squash-merge.