Cross Reference - client-side filtering

This patch implements advanced filtering for tabular data
retrieved from the backend (data initially filtered via the
inputs on the left page side).

Changes are available at: https://buildbot.dev.mariadb.org/cr

Details:

• Some columns now include dropdown boxes with multiple-choice unique values
  from backend results, allowing filtering by commit, branch,
  builder, test name, test variant, and type.
• The "Failure Text" field supports two modes:
  1. Regular substring search when a plain string is entered
  2. Regexp search when the pattern is enclosed in /.../, e.g.,
  /^(?!.OPT_PAGE_CHECKSUM).$/.