feature/add-validation

[fletchapin]

Pull request recommendations:

• [x] Name your pull request your-development-type/short-description. Ex: _feature/docfloc
• [x] Link to any relevant issue in the PR description. Ex: Resolves [gh-12], adds flocculator documentation
  • Resolves #47, resolves #33
• [x] Provide context of changes.
• [x] Provide relevant tests for your feature or bug fix.
• [x] Provide or update documentation for any feature added by your pull request.

Added an option to download a validation report PDF from the website using the same form that serves the documentation. This involved importing the new aide_validation PyPi package which will likely be merged into aguaclara in the future.

Manually tested as seen here:

[fletchapin]

One small issue is that I don't know how to limit the language drop down but it currently only supports reports in English despite the option for Spanish. I created this issue to fix that