Submodule-able Theme

Can now be pulled in as a themes/ submodule in Hugo projects. All preexisting content pages work and look the same as they did originally.

Changes include:

• Removed all non-theme essential pieces of original project
• Moved original content/, snippets/, and config into an exampleSite directory, in line with official Hugo themes guidelines (https://github.com/gohugoio/hugoThemes)
• Updated shortcode usage syntax to work with Hugo 0.55+

Changes based on personal preference:

• Converted all TOML to YAML