Update config to allow for a simpler setup by default

[joshdales]

Description:
Update the config so that you don't need to provide as many options to the changed-files option and that it works a bit more similarly to the v5 beta, however you can still provide all the advanced configuration options if you need or want to.

Basically this

test:
  - changed-files: 'glob'

is now the same as

test:
  any:
    - changed-files:
      - any-glob-to-any-file: ['glob']

If you provide an all key then it will then default to all-globs-match-all-files behaviour:

test:
  all:
    - changed-files: 'glob'

is the same as

test:
  all:
    - changed-files:
      - all-globs-to-all-files: ['glob']

This would also probably allow an easier upgrade from v4 to v5

Related issue:
#715

Check list:

• Mark if documentation changes are required.
• Mark if tests were added or updated to cover the changes.