We use the X-Leap-Signature and X-Leap-Encryption to signal the
signature and encryption status of emails. An attacker could add this
headers and trick bitmask to believe that the email was signed and/or
encrypted. Now we remove this headers from the original email if they
are present before adding ours.

- Resolves: #7429

To keep compatibility with soledad upgrades. It will namely cause version conflicts
to not be properly handled otherwise.

See https://github.com/pixelated/puppet-pixelated/issues/49

Do not initialize the openssl context on each call to get mail payload phash.

The openSSL backend should only be initialized once because it is activating the os random engine
which in turn unregister and free current engine first. This is very tricky when operations are running in threads
as it essentially momentarily unregister the openssl crypto callbacks that makes openssl thread safe.

- Resolves: #8180 with the soledad PR #324

- Resolves: #8177