feat: add Mount Migration support to all secrets/auth backends

[vinay-gopalan]

Adds mount migration support to all secrets/auth backends.

This PR removes the previously added semver package and instead moves those functions to meta.go instead. The ProviderMeta object now stores the Vault Version after making a call to the client.Sys().SealStatus() endpoint.

For testing, the best way I found to confirm that Mount Migration for secrets/auth mounts had successfully completed was by running a Remount test and then viewing the Vault logs to confirm that a Migration ID was dispatched, and the mount was moved accordingly:

2022-09-08T10:13:34.835-0700 [INFO]  core: successful mount: namespace="" path=tf-test-terraform-cloud-5084382457978848863/ type=terraform

2022-09-08T10:13:36.012-0700 [INFO]  core.mounts.migration: Starting to update the mount table and revoke leases: from_path=tf-test-terraform-cloud-5084382457978848863 migration_id=21d4beff-97c0-afac-974c-b18daf982bfd namespace="" to_path=tf-test-terraform-cloud-updated-8145651656808162423

2022-09-08T10:13:36.012-0700 [INFO]  core.mounts.migration: Removing the source mount from filtered paths on secondaries: from_path=tf-test-terraform-cloud-5084382457978848863 migration_id=21d4beff-97c0-afac-974c-b18daf982bfd namespace="" to_path=tf-test-terraform-cloud-updated-8145651656808162423

2022-09-08T10:13:36.012-0700 [INFO]  core.mounts.migration: Updating quotas associated with the source mount: from_path=tf-test-terraform-cloud-5084382457978848863 migration_id=21d4beff-97c0-afac-974c-b18daf982bfd namespace="" to_path=tf-test-terraform-cloud-updated-8145651656808162423

2022-09-08T10:13:36.012-0700 [INFO]  core.mounts.migration: Completed mount move operations: from_path=tf-test-terraform-cloud-5084382457978848863 migration_id=21d4beff-97c0-afac-974c-b18daf982bfd namespace="" to_path=tf-test-terraform-cloud-updated-8145651656808162423

2022-09-08T10:13:38.301-0700 [INFO]  core: successfully unmounted: path=tf-test-terraform-cloud-updated-8145651656808162423/ namespace=""

[benashz]

A few minor nits/suggestions to address; then 👍