Change attachment to document and update

Fixes #17

Incorporates ideas from other tickets e.g. id not documentID
Add documents to planning and remove publicHearingNotice

Also make id on document required to facilitate merging.

Fixes #95
Remove notices (capture through documents)

Fixes #123

Also bug fix reference to attachment and make use of documents consistent
throughout.
Improved amendment on tender, award, contract.

With the removal of notices, amendment information needed to be added to tender
and award.

The amendment block has been updated to include changes.

Fixes #106