Add Docsy dependency submodules (font-awesome and bootstrap)

[ferhoyos]

Trying to deploy kiali.io site locally with make serve command, I found the following error:

Error: command error: failed to load modules: module "github.com/FortAwesome/Font-Awesome" not found in "/site/themes/github.com/FortAwesome/Font-Awesome"; either add it as a Hugo Module or store it in "/site/themes".: module does not exist

After some investigation I figured out that font-awesome repository must be added in site/themes folder. The same happens for bootstrap.

Error: command error: failed to load modules: module "github.com/twbs/bootstrap" not found in "/site/themes/github.com/twbs/bootstrap"; either add it as a Hugo Module or store it in "/site/themes".: module does not exist

Adding these two repositories as git submodules fix the issue and let me deploy kiali.io locally.

[ferhoyos]

Closing since I have found a better solution here: #757