clean up catalog url query parameters

URL in catalog get unnecessary long. Some query parameter is not needed, some are duplicate.

## How to reproduce

- add `test` in the search box and submit
- click `Test' in the keyword filter

## Expected behavior
URL shows
https://catalog.data.gov/?q=test&keyword=Test

## Actual behavior
URL shows
https://catalog.data.gov/?sort=relevance&q=test&sort=relevance&spatial_filter=&keyword=test

## Sketch

No need to show default value such as emtpy string for spatial_filter and relevance for sort.

Start by tracing how the catalog search and keyword filter construct URL query parameters, then reproduce the steps with `q=test` and `keyword=Test`. Done means the URL omits duplicate parameters and default empty or relevance values, matching the expected URL in the issue.

Written by the indexing model from the issue text.