Maintain atomicity in membership service

[Aravindh-Raju]

Changes in this pull request:

• Created a transaction to maintain atomicity in MembershipService.scala where group, groupChange, membership data are changed without a tranaction. Now, either everything gets executed or none gets executed.
• Verified the transaction by running locally.

[codecov]

Codecov Report

Merging #1081 (a201bd8) into master (fb9bd16) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1081   +/-   ##
=======================================
  Coverage   92.69%   92.70%           
=======================================
  Files         169      169           
  Lines        6670     6676    +6     
  Branches      167      163    -4     
=======================================
+ Hits         6183     6189    +6     
  Misses        487      487           

Impacted Files	Coverage Δ
...core/domain/membership/GroupChangeRepository.scala	0.00% <ø> (ø)
...ldns/api/domain/membership/MembershipService.scala	94.65% <100.00%> (+0.25%)	⬆️
.../mysql/repository/MySqlGroupChangeRepository.scala	100.00% <100.00%> (ø)
...nyldns/mysql/repository/MySqlGroupRepository.scala	100.00% <100.00%> (ø)
...s/mysql/repository/MySqlMembershipRepository.scala	95.55% <100.00%> (ø)

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[remerle]

LGTM 👍