Fauxton: Implement a filter for changes

As code is duplicated, mode the filter to the component. Tthe filter
then can be overwritten if there anything special is needed.
review
rename js-log-filter-form to js-filter-form
remove sidebar filter, add header filter
make filtering case insensitive
use strong tag instead of a h6, change button to primary button color (red)
change <%= to <%- as <%= is not needed
we can add tooltips to a filter
make deleted documents searchable

they are missing an explicit deleted flag
add license header