Add action report to keep results from actions for monitoring an REST API

[greenhat]

Close #262

This PR introduces *ActionReport types created during the refresh and datapoint actions. Along with storage and access across all app modules (REST API now, health monitoring later).

[coveralls]

Pull Request Test Coverage Report for Build 5001140377

• 4 of 34 (11.76%) changed or added relevant lines in 6 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.3%) to 59.8%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
core/src/pool_commands.rs	0	3	0.0%
core/src/action_report.rs	0	7	0.0%
core/src/main.rs	0	8	0.0%
core/src/api.rs	0	12	0.0%

Files with Coverage Reduction	New Missed Lines	%
core/src/api.rs	1	0%
core/src/main.rs	1	0%

Totals
Change from base Build 4978549204:	-0.3%
Covered Lines:	2096
Relevant Lines:	3505

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💛 - Coveralls