Fix failing checks

* Remove double question to migrate
* Remove parallelism (it has been flaky)
* Add subtests to apply_auto_approve_test (it was overlooked before)

The specialized Terraform Cloud migration process asks right up top
whether the user wants to migrate state, because there are various other
questions contingent on that answer.

Therefore we ought to just honor their earlier answer when we get to the
point of actually doing the state migration, rather than prompting again.

This is tricky because we're otherwise just reusing a codepath that's
common to both modes. Hopefully we can find a better way to do this in
a later commit, but for the moment our main motivation is minimizing risk
to the very next release.

There are a few command line options for "terraform init" which are only
relevant when working with traditional backends, with the Cloud
integration previously just mostly ignoring them, or sometimes misbehaving
slightly due to them creating an unreasonable situation.

Now we'll catch these and return explicit errors, in order to be clear
that these options are not needed nor supported in Cloud mode.

This just gives a little extra information to work with when trying to
understand why a test failed. It doesn't change what any of the tests are
actually trying to test.

This aims to encapsulate the somewhat-weird logic we currently use to
distinguish between the various "terraform init" situations involving
Terraform Cloud mode, in the hope of making codepaths that branch based
on this slightly easier to read.

This isn't yet used, but uses of it will follow in subsequent commits.

This PR adds support for using MSAL instead of ADAL for getting auth tokens in the AzureRM backend, meaning that Microsoft Graph Tokens will be used rather than Azure Active Directory Graph Tokens.

For the moment this is an opt-in feature - however in a future release we'll flip the default from ADAL to MSAL since ADAL is deprecated.

Co-authored-by: Tom Bamford <tbamford@hashicorp.com>

Co-authored-by: Tom Bamford <tbamford@hashicorp.com>

Co-authored-by: Tom Bamford <tbamford@hashicorp.com>

Co-authored-by: Tom Bamford <tbamford@hashicorp.com>

Co-authored-by: Tom Bamford <tbamford@hashicorp.com>

This redirects to the registry so we should point there directly

Remove retracted k8s package

Signed-off-by: Jared Ledvina <jared.ledvina@datadoghq.com>

Use the latest k8s.io packages from v0.21

Cloud: Migrate empty default workspace prompt

This pull request focuses on removing the prompt to rename the default
workspace when it is empty. Functionality already exists to not migrate
an empty workspace. This commit adds some clarifying language in the
comment where we do the evaluation to know whether to ask for a new name
or not. I also added an end to end test, which I should have added to
begin with.

refactoring: error when changing resource type during move

Given: You have multiple explicit local workspaces, and the `default`
workspace is empty.
When: You migrate the workspaces to Terraform Cloud.
Then: Terraform should _not_ ask for a workspace to migrate the
`default` workspace to in Terraform Cloud.

funcs: defer close file in filesha256

Files opened by these two functions were not being closed,
leaking file descriptors. Close files that were opened when the
function exist.

Cloud: Make e2e Tests Less Chatty, and More Stable

Add cidr block output example to setproduct function page

Some small edits to the TFC migration copy.

AbsMoveableResource is an AbsMoveable that is either a resource or a resource
instance. This interface represents a moveable that has a resource type.