URL validation module

[Blackbaud-SteveBrush]

We'll consider combining all validators into a single "Validation" module based on @Blackbaud-JeffDye's work, here: #1248

Addresses: #1232

[Blackbaud-JeffDye]

Looks good to me!

[codecov-io]

Codecov Report

Merging #1334 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff           @@
##           master   #1334   +/-   ##
======================================
  Coverage     100%    100%           
======================================
  Files         362     364    +2     
  Lines        6704    6723   +19     
  Branches      863     865    +2     
======================================
+ Hits         6704    6723   +19

Impacted Files	Coverage Δ
...modules/url-validation/url-validation.directive.ts	100% <100%> (ø)
...rc/modules/url-validation/url-validation.module.ts	100% <100%> (ø)

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