Pangene Revisions

[alancleary]

This PR includes the following changes:

• Clicking the download button in a search component no longer resets the page count; Issue Pangene lookup component's download button resets pangination #400
• Generally, search components now support an inline downloading indicator. This is intended for search forms that contain a download button. The pangene lookup component is utilizing this functionality.
• Previously the paginated search mixin was separated into two mixins: a search mixin and a paginated search mixin that extends the search mixin. This has been undone due to excessive code replication, difficulty in extending the code, and because no components were actually using the non-paginated mixin. I believe this fixes issue Querystring parameter back functionality is misbehaiving in search components #390. It appears to have also fixed issue No form data function provided #285, although that was unintended!
• Querystring reflection is now optional for all search components but is enabled by default.
• The pangene lookup component no longer has querystring reflection. This fixes issue pangene lookup can break by 414: Request-URI Too Long #399

[adf-ncgr]

hmm, looks like the fix did not actually solve #399 or else has transformed it into something a little different (my bad for not supplying more detail in that issue, going to update it now with some more info about what I'm seeing)