GF Template repo files

[vv-monsalve]

HI @rfuenzalida,

This PR includes:

• [x] I have restored the previous vertical metrics values after testing some intermediate values. I confirmed that the previous values work better with the font's display character, with only a small compromise for the stacked diacritics.
• [x] Incorporates the googlefonts-project-template files to the repo so it will create a .zip package that will include the fonts plus all the testing and proofing files every time you push a source file to the master branch. This way, we ensure the font building using our tools, as it is one of our production requirements :) Please have a look at the template to get familiar with how you could build the fonts locally.

Please merge this PR before continuing to work on the font.

[rfuenzalida]

New files merged, waiting for comments on SSA to move forward.