Add support for using either the CFS v2 or v3 API in `sat bootprep`
based on the value of the command-line option `--cfs-version` or the
config-file option `cfs.api_version`. Before this change, `sat bootprep`
was hard-coded to always use CFS v2.

Update the `InputConfiguration`, `InputConfigurationLayer`, and
`AdditionalInventory` classes to keep a reference to the instance of the
version-specific subclass of `CFSClientBase`, so that they can delegate
operations to the appropriate version of the CFS API.

This removes a lot of code that required knowledge of the CFS API and
instead uses classes and methods defined in the `csm_api_client`
library, which has already been updated to support both CFS v2 and v3.
This should reduce code duplication across `sat` and `csm_api_client`.

Some unit tests are no longer needed here because that functionality is
tested in the `csm_api_client` instead. Other unit tests are updated to
include the `cfs_client` instance that needs to be passed into the input
layer and configuration objects.

This also makes the `playbook` property required in the schema because
the CFS v3 API requires that the playbook be specified. This is
technically a backwards-incompatible schema change because it can
invalidate certain bootprep input files if they define layers without
playbooks. The default bootprep files contain a playbook for every
layer and do not depend on the CFS default playbook value, so this
should be a pretty safe and non-disruptive change.

Test Description:
Unit tests only so far.

Still needs to be tested on a real system.

The CFS v3 API returns paged results for the `/components` API resource,
which needs to be handled by the client. Upgrade the version of the
csm_api_client library and use the new `get_configurations` method to
handle the paging.

Test Description:
Not yet tested.

If the value "latest" is specified for the version of a product in a
product-based layer in a CFS configuration in a bootprep input file,
pass in `None` to `from_product_catalog` to properly get the product
catalog data associated with the latest version of the product.

Test Description:
Not tested yet.

Add the `--cfs-version` command-line option to `sat bootprep run`. This
option is used to select the version of the CFS API to use when creating
CFS configurations or checking for the existence of CFS configurations
when creating other items in the bootprep input file.

Add this option to the man page as well.

Test Description:
Built man page and examined in `man`.

Other testing yet to be performed on a system.

A delay has been observed in `sat bootprep`, and it may be due to the
loading of product catalog data taking longer with the split product
catalog config maps. Add a debug-level log message before and after
loading the product catalog, so we can see what's happening.

Instead of requiring that the playbook be present in the bootprep input
file through the schema, validate it specifically when `sat` is
configured to use the CFS v3 API, since the CFS v2 API does not require
that CFS configuration layers have a playbook. This will allow people to
continue using old bootprep input files that have CFS configuration
layers that do not specify a playbook as long as they use CFS v2. This
is slightly less disruptive than making a schema change.

Test Description:
Unit tests only so far.

The `InputConfigurationLayer` instances stored in the `layers` attribute
of the `InputConfiguration` class were not being validated when the
`validate` method of the `InputConfiguration` was called because this
class did not have any validation methods. Add a validation method that
validates the layers, and make the `InputConfigurationLayer` class
inherit from `Validatable`, so that it has a `validate` method itself.

This has not been added for `AdditionalInventoryLayer` yet because there
are currently no validation methods on that class.

Note that an `index` is added to the constructor of the
`InputConfigurationLayer` class to allow for the `__str__` to
unambiguously refer to the layer within the CFS configuration.

Test Description:
Unit tests have been added to test the `validate` method on the
`InputConfiguration` class.

Add support for Jinja2 template rendering to several more properties in
the `sat bootprep` input file. The following properties now support
Jinja2 templating:

- configurations[].layers[].git.commit
- configurations[].layers[].git.url
- configurations[].layers[].product.commit
- All properties under images[].base.ims
- session_templates[].image.ims.id

Allowing Jinja2 template rendering for these fields is helpful in
writing automated test cases for `sat bootprep` that can run on any
system. These values will vary from system to system, so it's helpful to
pass this information in to the bootprep input file as a variable.

Test Description:
Added unit tests pass. Will also be tested on a system with bootprep
input files that use Jinja templates in these properties.

Add support for Jinja template rendering to the `name`, `url`, `branch`,
and `commit` properties of the `additional_inventory` of a CFS
configuration specified in a bootprep input file.

This is useful for writing automated tests that obtain this information
from a system and pass it in through variables with `--vars-file`.

Test Description:
The added unit tests pass, and it will be tested on rocket as well.