Fixes #6182

* Fixes a regression in forwarding from #6115

Although removing the authentication header is good defense in depth,
for forwarding mechanisms that use the raw request, we never add it
back. This caused perf standby tests to throw errors. Instead, once
we're past the point at which we would do any raw forwarding, but before
routing the request, remove the header.

To speed this up, a flag is set in the logical.Request to indicate where
the token is sourced from. That way we don't iterate through maps
unnecessarily.

* Adds the ability to enforce particular ssh key types and minimum key
lengths when using Signed SSH Certificates via the SSH Secret Engine.

* Merge entities during unseal only on the primary

* Add another guard check

* Add perf standby to the check

* Make primary to not differ from case-insensitivity status w.r.t secondaries

* Ensure mutual exclusivity between loading and invalidations

* Both primary and secondaries won't persist during startup and invalidations

* Allow primary to persist when loading case sensitively

* Using core.perfStandby

* Add a tweak in core for testing

* Address review feedback

* update memdb but not storage in secondaries

* Wire all the things directly do mergeEntity

* Fix persist behavior

* Address review feedback

* Add SHA1 signing/verification support to transit engine

* Update signing/verification endpoint documentation to include sha1 hash algorithm

Documentation : Add the supported log level configurations

`Supported log levels: Trace, Debug, Error, Warn, Info.`

* return a more helpful err msg

* update test, print fmt

* fix other test failure

* Two things:

* Change how we populate and clear leader UUID. This fixes a case where
if a standby disconnects from an active node and reconnects, without the
active node restarting, the UUID doesn't change so triggers on a new
active node don't get run.

* Add a bunch of test helpers and minor updates to things.

This reverts commit 4310bb58.

Accidental push to master, my apologies. See PR https://github.com/hashicorp/vault/pull/6175