Refactoring of dapps broke local installed apps display

[jacogr]

2 paths -

1. built-ins, hardcoded at this point, to be retrieved from dappreg (along with others) in teh future
2. local apps, retrieved via /api/apps

Second option doesn't get called at this point.

In additon, the id field is wrongly named for built-ins, the sha3(name) is the actual ID as registered, it needs to be available. For built-ins the final path is overwritten, so id -> url, id to be added

1. For external apps, id is the GithubHint contenthash (which also doubles as the dappreg id), apps loaded from 127.0.0.1:8080/ or .parity/
2. For built-ins, the url is where the apps are loaded from, 127.0.0.1:8080/ui/.html - image retrieved from dappreg(id)->meta()->contentHash

Bear in mind the built-ins are not fetched from GithubHint and neither do they have the associated manifest. The hardcoded list of apps mimics the manifest structure, 1-to-1, so we have a built-in manifest.

[jacogr]

Update when https://github.com/ethcore/parity/pull/2793 merged