Feature adds for controller scan

[jhenson29]

Sample of suggested updates for Controller scan

Description, Motivation, and Context

Adds ability to remove and query tags in the subscription group.
Adds ability to set scan for read only
Check elapsed time for scan and modifies wait time accordingly so update rate is close to set scan rate.
Added scan min overhead percent to keep a minimum amount of wait time relative to the task time

How Has This Been Tested?

Minimal testing against a PLC

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• This is a work in progress, and I want some feedback (If yes, please mark it in the title -> e.g. [WIP] Some awesome PR title)

Related Issue

[coveralls]

Pull Request Test Coverage Report for Build 73

• 17 of 22 (77.27%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+1.0%) to 51.133%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/controller/index.js	15	20	75.0%

Totals
Change from base Build 70:	1.0%
Covered Lines:	431
Relevant Lines:	810

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💛 - Coveralls