Show "please wait" message when Nature services are starting

[odeimaiz]

What do these changes do?

Demo showing the message in the 2D plot service:

Related issue/s

How to test

Checklist

[codecov]

Codecov Report

Merging #2801 (8e45b97) into master (48d28c1) will decrease coverage by 0.0%.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           master   #2801     +/-   ##
========================================
- Coverage    78.8%   78.8%   -0.1%     
========================================
  Files         670     670             
  Lines       27186   27186             
  Branches     2669    2669             
========================================
- Hits        21445   21440      -5     
- Misses       4982    4986      +4     
- Partials      759     760      +1     

Flag	Coverage Δ
integrationtests	65.9% <ø> (-0.1%)	⬇️
unittests	74.4% <ø> (+<0.1%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...vice_director_v2/modules/dynamic_sidecar/errors.py	82.6% <0.0%> (-17.4%)	⬇️
...tor_v2/modules/dynamic_sidecar/scheduler/events.py	94.1% <0.0%> (-1.8%)	⬇️
..._director_v2/modules/dynamic_sidecar/client_api.py	80.7% <0.0%> (-1.5%)	⬇️
...simcore_service_director_v2/modules/dask_client.py	82.6% <0.0%> (+0.6%)	⬆️
...ce_webserver/resource_manager/garbage_collector.py	73.5% <0.0%> (+0.8%)	⬆️
...simcore_service_webserver/projects/project_lock.py	100.0% <0.0%> (+5.2%)	⬆️

[KZzizzle]

brilliant