Add support for globalThis inside of templates to reference the global scope

[zachleat]

Could solve the problem of trying to reference top level globals with dashes in the name

#567 #1535

Moderate overlap with #874
Marginal overlap with #1060
Unconfirmed overlap with #1541

[zachleat]

https://node.green/ has globalThis support in Node at 12+ but for the record this would just be faking it for template-land vars

[zachleat]

Could even use approaches in #567 like @edwardhorsford’s: #567 (comment)