Create namespaces on db creation

[nitro-neal]

Currently we do an empty write to the credential bolt db to get around a bug where if you do a read before anything is written it will throw an error

it's because the namespace bolt is using is created on first write. we should open up another issue to address it.
solutions:

seed the DB with a first entry
detect the namespace not exists error and throw another error

[andresuribe87]

@nitro-neal is this still an issue?

[nitro-neal]

This was fixed with this - #241