Link username to user tests page from tests_view pages

[linrock]

Fixes #625 (comment) as suggested by @silversolver1

I mean on the page of an actual test where a user can access the stop/purge, reschedule or modify buttons, next to where the value for itp is listed, there is the word "username". here, the user's particular name does not currently link to that user's /tests/user/ page, which is the feature I am suggesting

I agree this is more practical since I've also commonly wanted to go see a list of the user's tests while on an individual test page.

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Approvers will see a link to the user admin page in addition to the link to the user tests page.

[ppigazzini]

Tested OK on DEV, PROD updated, thank you @linrock :)