Update templates for mandatory componentization

[lann]

The Swift template is no longer usable due to the deprecation of running uncomponentized modules and issues with componentizing: #2774

The Grain template has been updated based on upstream advice: grain-lang/grain#2153

Closes #2774

[itowlson]

There are some tests in the templates crate that use the templates from the Spin repo and make assertions by counting. The const for the expected total count is called TPLS_IN_THIS and will (I expect) need to be updated for 'unit' tests to pass.

spin/crates/templates/src/manager.rs

Line 569 in 09de9c3

const TPLS_IN_THIS: usize = 12;