Add metadata permissions

[dxenes1]

Permission modifications to separate resource and metadata permissions.

Use cases:

1. Allow external collaborators to write metadata but not modify public spatial data.
2. Allow groups to manage metadata to update the website automatically.
3. Allow secondary analysis groups to access and write metadata for projects they are working with

Permission Groups

	read resource	add resource	update resource	delete resource	read metadata	add metadata	update metadata	delete metadata
read	x				x
read+addmeta	x				x	x
read+fullmeta	x				x	x	x	x
write	x	x	x		x	x	x	x
admin	x	x	x		x	x	x	x
admin+delete	x	x	x	x	x	x	x	x

[dxenes1]

I think all requested changes should be addressed in the latest commit, but please let me know if I missed anything!

[movestill]

I see lots of old code that could use refactoring, but I think your changes for metadata look good!

The base branch was changed.