Updating provider-defined functions to use named parameters

[bendbennett]

With the update to the plugin framework that now requires all provider-defined function parameters are named, this repo needs to be updated to add parameter names throughout.

Changes were evaluated by:

• Building a local Terraform binary from v1.8.0-beta1
• Temporarily switching all tfversion.SkipBelow(tfversion.Version1_8_0) to tfversion.SkipBelow(tfversion.Version1_7_0)
• Temporarily updating go.mod to use the branch of the plugin framework containing the changes requiring all function parameters are named.
• Running the tests

During the execution of the tests, it was discovered that TestNumberFunction_known was failing. This was raised as an issue on the Terraform core repo - Planned value does not match config value for number. A note was made within the tests to refer to this issue:

	// Using 9223372036854775808, the smallest number that can't be represented as an int64,
	// results in an Terraform error where [Planned value does not match config value for number].
	// A value of 9223372036854775809 is used for the meanwhile.
	//
	// [Planned value does not match config value for number]: https://github.com/hashicorp/terraform/issues/34866

[bflad]

Looks good to me

[github-actions]

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