Filesize of dictionary

[DanielHeath]

It looks like dictionary.ts stores several fields that shouldn't really be needed. Everyone who visits the page needs to download & parse it, and it's 1.1mb.

[DanielHeath]

I've made a couple of commits stripping it down to 300kb or so. Old versions of the file are still in git, so if we find a use for that data in future we can always pull it back out.

[plwp]

There needs to be a map from tag id to VR for implicit VR parsing I've seen it done functionally in some of the dicom-parser examples but I don't know how robust that would be (or if it's worth introducing errors).

Even if the tags aren't used in policy they might be used in parsing the data for some cases.