Fixes#9708.
Matches the kmp.json format of keys string in the .keyboard_info schema
and compiler, in order to reduce the number of formats we are working
with. This same format may be used elsewhere in Keyman schemas in the
future for sets of keys, for example, I hope we can use it in regression
tests.
Fixes#9620.
.keyboard_info keys emitted from kmc-keyboard-info had the wrong format
for the example.keys object, which I discovered when I applied the
validation to the kmc-keyboard-info output.
Removes the following fields:
* legacyId
* documentationFilename
* documentationFileSize
* links
* related[].note
None of these fields are needed any longer; see #9351 for steps to
remove data.
Eliminates difference between keyboard_info source and distribution,
renaming to keyboard_info.schema.json, and updating the required members
of the json accordingly.
Will have corresponding commits in keyman.com, api.keyman.com,
help.keyman.com, and keyboards repositories.
