Transpilers should become Templates

[StartAutomating]

See #832

Essentially, the internal plumbing of PipeScript is currently called "transpilers". These are effectively a very old command type, built using Piecemeal.

Logically, we can think of these as "Strongly Piped Templates for PowerShell or PipeScript", and, eventually, have one less category of things to talk about.

• [ ] #981
• [ ] #982
• [ ] #983
• [ ] #984
• [ ] #985
• [ ] #986
• [ ] #987
• [ ] #988
• [ ] #989
• [ ] #990
• [ ] #991
• [ ] #992
• [ ] #993
• [ ] #994
• [ ] #995
• [ ] #996
• [ ] #997
• [ ] #998
• [ ] #999

A subsection of existing transpilers are categorized as "Keyword"s. These cases will require special attention:

• [ ] #1116