update on the snews tier publisher

[KaraMelih]

• It allows for environment setting (this is needed if the user doesn't pass detector name, it tries to fetch from env)
• can read from json file (simple from_json() method, parses and passes this data)
• arbitrary number of key-value pairs; init takes env_file=None, **kwargs and anything can be passed, it is looked in the snews_pt_utils._tier_decider and both the messages and which tiers found is returned
• it keeps the messages and tiers as attributes; the messages and tiernames (see above) are appended as attribute thus;

from SNEWS_PT.snews_pub import SNEWSTiersPublisher
snews = SNEWSTiersPublisher(detector_name='KamLAND', timing_series=['4:31:05:565', '4:31:05:575', '4:31:05:585'],
                                                  p_val=0.000007, p_values=[0.000007, 0.000004], machine_time='22/02/08 4:31:08:565')

can be further investigated before submitting a message i.e.

print(snews.messages)
print(snews.tiernames)

and finally snews.send_to_snews() submits the message.

Alternatively;

from SNEWS_PT.snews_pub import SNEWSTiersPublisher
snews = SNEWSTiersPublisher().from_json('myjsonfile.json')
snews.send_to_snews()

[KaraMelih]

@Storreslara Today we were working on your branch which is why I created this PR for your branch. Once a PR is created it is easier to compare the changes. Could you please have a look and maybe we can go over the lines by commenting?

[KaraMelih]

In this 5cb1ac37ff1d4d6533280d56f64a209d1b5ce2e4 commit, I changed the key 'nu_time' to 'neutrino_time' and also 'p_value' to 'p_val'