[webservice] Select partition based on beamtime dates

Description

Beamtimes can be active for a longer period of time, even though there is no user experiment ongoing, for reasons such as compensation time.
This leads to a problem where the jobs for such proposals are ran with high priority, although they're on ongoing. MyMDC provides information regarding the beamtime, on top of the proposal status, with the begin and end dates.

These dates, as well as the proposal status, are now used to select the correct slurm partition.

How Has This Been Tested?

The changes were tested with the test installation with the following settings:

Proposal	Run	Action	Proposal Status	Beamtime	Expected Partition
900113	9999	correct	FR	2019-12-12T13:54:29.000+01:00 - 2019-12-17T13:54:29.000+01:00	exfel
900113	9999	correct	A	2019-12-17T13:54:29.000+01:00 - 2019-12-17T13:54:29.000+01:00	exfel
3014	267	dark	FR	2022-08-31T15:29:37.902435 - 2022-09-02T15:30:06.322790 (ongoing as of this MR)	upex-high
3014	267	correct	A	2022-08-31T15:29:37.902435 - 2022-09-02T15:30:06.322790 (ongoing as of this MR)	upex-middle

Note that the replies from MyMDC were intercepted to change the beamtime dates and proposal status.

Tests were added to check for various scenarios.

Relevant Documents (optional)

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I added tests where appropriate.

Reviewers

@roscar @schmidtp

webservice/webservice.py

@@ -550,9 +550,6 @@ async def get_slurm_partition(
     # | CLO  | Closed       | Data fully migrated to dCACHE          |
     # |------|--------------|----------------------------------------|
 
-    # A proposal can have several beamtimes during which data can be taken,
-    # which are independent from the start and end dates.
-
     loop = get_event_loop()
 
     response = await shield(
@@ -577,6 +574,8 @@ async def get_slurm_partition(
     if status_beamtime in ['R', 'A']:
         partition = 'upex-high' if action == 'dark' else 'upex-middle'
 
+    # A proposal can have several beamtimes during which data can be taken
+    # that are independent from the start and end dates.
     beamtimes = response.json().get('beamtimes', [])
     active_now = False
     now = datetime.now().timestamp()
@@ -588,7 +587,6 @@ async def get_slurm_partition(
             break
     partition = partition if active_now else 'exfel'
 
-
     # NOTE: non-zero at cycle index 4 (`str(cycle)[4]`) indicates commissioning
     if run_id and cycle and str(cycle)[4] != '0':
         response_run = await shield(