Adapt platform to new soledad server entrypoints

Soledad server now has 2 distinct entrypoints:

• a publicly accessible api for users synchronization. TLS is currently handled by soledad server, but we want to move it to nginx so soledad doesn't need to care about this.
• a locally accessible api for mail delivery. This should be accessible by the MX node, so it needs an stunnel config when MX and soledad server run in distinct nodes.

In order to support that, the platform has to:

• #8830 Make Soledad Services API accessible from MX node
• #8869 Add blobs options to Soledad Server configuration template
• #8857 Configure a token for MX access to Incoming API Soledad Server
• #8874 Decide on a mail delivery upgrade workflow