Test execution search and query params

Resolves RTW-244 and closes #140 and #121

Changes:

Refactor filters and search components to be reused across dashboard and artefact page
In artefact page, add search by environment name (note Ctrl+F focuses on this search box :) )
In artefact page, persist search and filters as query parameters in url
Fix bug indicated by #140
Fix bug where approving or rejecting a testexecution/environment causes the filters to reset

canonical / test_observer