Upgrade format filter to advanced filter.

[mattcoley]

Making this an advanced filter allows us to do more powerful formats. For example, '%,d'|format(10000) to format the number to use commas: 10,000.

[codecov-io]

Codecov Report

Merging #279 into master will not change coverage.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master     #279   +/-   ##
=========================================
  Coverage     72.35%   72.35%           
  Complexity     1483     1483           
=========================================
  Files           231      231           
  Lines          4597     4597           
  Branches        737      737           
=========================================
  Hits           3326     3326           
  Misses         1016     1016           
  Partials        255      255

Impacted Files	Coverage Δ	Complexity Δ
...a/com/hubspot/jinjava/lib/filter/FormatFilter.java	100% <100%> (ø)	3 <1> (ø)	⬇️

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