Added support for Exclusive flag parameter which ensures the a value is the EXCLUSIVE value in a given key.

[bobbytreed]

Other resources (like UserRightsAssignment) perform this operation with the FORCE parameter. Here the FORCE parameter is used to remove Keys that have subkeys. Other names can be considered, but a flag is the most logical option. The impact is low for this change as current implementations would not at all be affected.

Fixes #63

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This change is 

[codecov-io]

Codecov Report

Merging #64 into dev will decrease coverage by <1%. The diff coverage is 65%.

@@         Coverage Diff         @@
##            dev    #64   +/-   ##
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- Coverage    83%    83%   -1%     
===================================
  Files        19     19           
  Lines      2751   2780   +29     
  Branches      4      5    +1     
===================================
+ Hits       2294   2313   +19     
- Misses      453    462    +9     
- Partials      4      5    +1

[zjalexander]

Discussing some design patterns with Bobby offline.

[mbreakey3]

Are there any updates on this PR or has it been abandoned for the time being?

[zjalexander]

We were discussing design implications with Mark. Since Mark has moved on, let me loop @mgreenegit in.

[johlju]

@mgreenegit Can you glance at this PR so we can remove the 'on hold' label, and then we can review it.

@bobbytreed Are you still able to work on this issue if we can remove the 'on hold' label?