Allow target count returns from len(Service) calls

[caronc]

Description:

Related issue (if applicable): n/a

This is just a change to the underlining API. A call to len(BaseService) will now return the number of targets configured to be notified.

Some plugins support a batch mode ?batch=yes. In these cases, the fact that a lot of targets can all be lumped into a single API call by apprise is factored into the len() call. The return will be set to the number of API calls needed to deliver the payload instead of the target counts in this case.

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• No lint errors (use flake8)
• 100% test coverage

Testing

Anyone can help test this source code as follows:

# Create a virtual environment to work in as follows:
python3 -m venv apprise

# Change into our new directory
cd apprise

# Activate our virtual environment
source bin/activate

# Install the branch
pip install git+https://github.com/caronc/apprise.git@target-counts

# launch a python instance
python

# The following commands assume you're now in a python interpreter:
import apprise

aobj = apprise.Apprise()

aobj.add('mailto://user:pass@localhost/abc@yahoo.ca/def@yahoo.ca')

# len() on the service object inside now returns the number of targets
# We added 2 emails to the above plugin, so the first internal object added
# to our apprise object (a NotifyMail() class) will return 2 when len()
# is called on it.
assert len(aobj[0]) == 2

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (00ddb09) 100.00% compared to head (52ea3cf) 100.00%.

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Additional details and impacted files

@@            Coverage Diff             @@
##            master      #874    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files          118       118            
  Lines        15377     15572   +195     
  Branches      3154      3173    +19     
==========================================
+ Hits         15377     15572   +195     

Impacted Files	Coverage Δ
apprise/URLBase.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyBark.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyBoxcar.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyBulkSMS.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyClickSend.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyD7Networks.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyDapnet.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyDingTalk.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyEmail.py	100.00% <100.00%> (ø)
apprise/plugins/NotifyFCM/__init__.py	100.00% <100.00%> (ø)
... and 42 more

... and 2 files with indirect coverage changes

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