remove user schema from the column search

[kimakan]

Closes #178

[coveralls]

Pull Request Test Coverage Report for Build 5552312359

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 64.068%

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Totals
Change from base Build 5483593982:	0.0%
Covered Lines:	4700
Relevant Lines:	7336

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💛 - Coveralls

[kimakan]

I have simplified and fixed the control for the rendering of the tooltips. Previously, the tooltips stayed rendered forever sometimes due to the re-rendering of the user_schema. In the old solution, I just turned off the tooltips for the user_schema but it's not a nice way of doing it. Now, the tooltips are shown for every schema, table and column. I ensure that no tooltip stays rendered forever by hiding all tooltips on the webpage after the mouseover event is over.