tezt: teztcloud improvements

What

• This MR improve the retrieval time of logs and profiling when teztcloud experiment are terminated
• Allow user to use the teztale report tab

Why

How

• By switching from a Lwt_list.iter_s to a Lwt_list.iter_p
• By adding a max_batch_op in the teztale config

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR