Optimizing parsing .bru files while program starts

[SPIRIT-00]

I have checked the following:

• I've searched existing issues and found nothing related to my issue.

Describe the feature you want to add

I've large collections, about 3,8k files. And each start of program be like: "launch Bruno and go away...". In many cases i need just a few specific reqs, not all collection.

I suggest:

1. Do not block all interface while files in load, just block top level folders* inside collection if not all inner files (recursively) was loaded.
2. Unblock top level folders after it was fully loaded, one by one.
3. Load folder in priority if user clicked on it, then continue load by sequence from top to bottom of folder list.
4. It may help mitigate this bug 'Requests' freezing while moving it between folders by drags #2613 if do update states of folders (not recursively) when transfer requests from folder to folder.

*Top level folders means one step after collection level:

• Collection
  • folder
  • folder
  • folder

Probably be solved by this pr #3618

Mockups or Images of the feature

[sreelakshmi-bruno]

Thanks for reporting, adding it to our development pipeline.