Updated flow limit pause resume functions, and fixed env issue for Ru…

[jdattatr-tibco]

…nnerQueueSize

What kind of change does this PR introduce? (check one with "x")

[x] Bugfix
[] Feature
[] Code style update (formatting, local variables)
[x] Refactoring (no functional changes, no api changes)
[] Other... Please describe:

Fixes: #
Fixed env issue for RunnerQueueSize where Legacy env variable was not used.
Refactored code for pause and resume trigger functions for flow limit feature.

What is the current behavior?
If new env variable(FLOGO_RUNNER_QUEUE_SIZE) is not set and legacy env variable(FLOGO_RUNNER_QUEUE) is set, it will pick default queue size(50)

What is the new behavior?
If new env variable(FLOGO_RUNNER_QUEUE_SIZE) is not set and legacy env variable(FLOGO_RUNNER_QUEUE) is set, it will pick legacy env variable.