Add `coder_workspace_owner` data source

[matifali]

Extracted from coder/envbuilder#174 (comment)

The properties that are per user and not per workspace should be added/refactored to the new data source, coder_user.

Other properties that should be added or moved from coder_workspace can be

1. coder_workspace.owner -> coder_user.name
2. coder_workspace.owner_name -> coder_user.full_name
3. coder_workspace.owner_email -> coder_user.email
4. Add coder_user.private_ssh_key (sensitive)
5. Add coder_user.public_ssh_key
6. Add coder_user.groups (A list of all groups if applicable)

[johnstcn]

Wrinkle: "groups" can apparently contain any arbitrary data, which is going to be a headache.

coder/coder#13354

[johnstcn]

Wrinkle: we'll also need to send this information from Coder (separate issue)

[johnstcn]

For the sake of clarity, this datasource will instead be named coder_workspace_owner as it will refer to information about the workspace owner and not the user creating the workspace.

[johnstcn]

Part 1 is here: #230
Next step: add a coder/coder change to send this information.

[matifali]

There is a related request to expose the user's timezone settings in #213.

Additionally, we can expose account type, i.e., password, github, oidc, or none (could be extracted to a new issue)