Haketilo

validate repository responses against JSON schemas

• compute_scripts.awk (include_file): don't enforce specific path format on #INCLUDE'd files
• .gitmodules, schemas: add Haketilo JSON schemas subrepo
• html/install.js (InstallView): import schema validator and run it against downloaded mapping and resource definitions...

fix URL construction when downloading definitions from Hydrilla

assume and use "$schema" properties in item definitions

change store names and data keys to singular

make resource dependency specifier an object

adapt to changes in file path format

From now on we assume Hydrilla serves file contents at 'file/sha256/' instead of 'file/sha256-'.
With this commit we also stop using the "hash_key" property internally.

add a repo querying HTML interface

add a mapping/resources installation dialog