Fixed missing sync module arm method

[fronzbot]

Description:

Add sync module arm and disarm methods back since they were inadvertently removed in the last rc release

Related issue (if applicable): fixes #298

Checklist:

• Local tests with tox run successfully PR cannot be meged unless tests pass
• Changes tested locally to ensure platform still works as intended
• Tests added to verify new code works

[codecov]

Codecov Report

Merging #299 into dev will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##              dev     #299   +/-   ##
=======================================
  Coverage   82.09%   82.09%           
=======================================
  Files           8        8           
  Lines         899      899           
=======================================
  Hits          738      738           
  Misses        161      161           

Flag	Coverage Δ
#unittests	82.09% <0.00%> (ø)

Impacted Files	Coverage Δ
blinkpy/sync_module.py	86.91% <0.00%> (ø)

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