On clean remote data button and checks

Improvements to be implemented:

- [ ] We should check only once if the `CalcJobNode` are empty, not eveytime we load the page/workchain. Now, for each `CalcJobNode`, we check the `is_empty` attribute. We need to verify that this is does not open ssh connections each time is it accesssed (see if it is a `property`). If each time it connects to remote, we should instead store an extra `is_empty` in the workchain, and then we only check if this attribute is not set.
- [ ] The clean button remains red even if it is disabled. We should change the color (grey).
- [ ] We should somehow also estimate the size of the remote data, so the user can decide if delete or not. See this PR in aiida-core by @GeigerJ2 : https://github.com/aiidateam/aiida-core/pull/6584

This is a follow-up of https://github.com/aiidalab/aiidalab-qe/issues/815