Fix config file on the webpage

[xylar]

The name of the complete config file should now be correct, so that the link works.

The control and main config files are also included if they are supplied.

closes #911

[xylar]

Testing

I tested this branch and #898 to produce these results:
https://web.lcrc.anl.gov/public/e3sm/diagnostic_output/ac.xylar/analysis_testing/bsf_main_vs_ctrl/main/clim_0001-0020_ts_0001-0020/

All 4 config files (main vs. ctrl, main, ctrl and complete) are there and links work. I put back ${webportal:username} extended interpolation in the config file and it works now even in the main and ctrl config files.

[xylar]

@anirban89, I had put you as a reviewer but I think my testing is sufficient. I'll just merge once the continuous integration (CI) tests from Azure finish, which should be soon.