General: add templates to render change annex

[ronaldtse]

The change annex exists in all documents including the resource and module docs.

There needs to be two types of change templates:

• for resource docs, render:

  • change.yaml for the resource schemas (many)
  • change.yaml for the document itself

• For module docs, render:

  • mapping changes
  • change.yaml for the ARM schema (one)
  • change.yaml for the MIM schema (one)
  • change.yaml for the document itself

[ronaldtse]

Done in #15. Thanks @manuelfuenmayor !

[manuelfuenmayor]

Change template for resource documents is pending.

[TRThurman]

For module docs, there is also

• change for arm long form (optional, depends on existence of arm_lf.exp)
• change for mim long form (optional, depends on existence of mim_lf.exp)