[API] allow searching for a list of object ID

[JulienPeloton]

The objects API only allows to query for one object at a time:

import requests
import pandas as pd

# get data for ZTF21aaxtctv
r = requests.post(
  'https://fink-portal.org/api/v1/objects',
  json={
    'objectId': 'ZTF21aaxtctv',
    'output-format': 'json'
  }
)

# Format output in a DataFrame
pdf = pd.read_json(r.content)

When we want to search for many candidates, we loop over on the client side. But this is inefficient (many communications between the client and the server), and it would be better to group all objectId in one query:

import requests
import pandas as pd

mylist = ['ZTF21aaxtctv', 'ZTF21abfmbix', 'ZTF21abfaohe']

# get data for many objects
r = requests.post(
  'https://fink-portal.org/api/v1/objects',
  json={
    'objectId': ','.join(mylist),
    'output-format': 'json'
  }
)

# Format output in a DataFrame
pdf = pd.read_json(r.content)