Trims whitespace from pipeline params on creation of new run

[rileyjbauer]

Fixes #162

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This change is 

[rileyjbauer]

/retest kubeflow-pipeline-sample-test

[rileyjbauer]

/test kubeflow-pipeline-sample-test

[gaoning777]

@SinaChavoshi What do you think of trimming the spaces in the pipeline input?

[Ark-kun]

/lgtm

[gaoning777]

verified with sina offline. It's reasonable to trim the spaces/tabs in the input params during the run creation.
/lgtm

[rileyjbauer]

/approve

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[rileyjbauer]

/test kubeflow-pipeline-e2e-test

[Ark-kun]

/lgtm
Note that in future we might start getting requests to add the ability to turn this off.
There are some legitimate cases to want control over whitespace. The simplest is when the user wants to specify column separator character (usually space or tab).