TLS for slave HTTP

[janisstreib]

I prupose the follwing procedure:

• Each slave has its (not necessarily unique) cert and private key, signed by a cluster local CA and supplied via the cmd.
• When the mater connects to the slave, it only allows connections with certs signed by the CA.
• The CA/PKI structure will not be managed by the master.

=> Therefore I prupose to place the CA cert into the master as reference to simplify the implementation.

• Add cert/key parameters to the slave cmd
• Serve http with TLS instead of plain HTTP on the slave
  • Only use proper ciphers, please ;)
• Use http with TLS + client cert instead of plain HTTP on the master
• Configure the CA in the master
  • (Optional) Add CA to MaterAPI (/api/system)
  • (Optional) Add GUI setting or display for the CA
  • Alternatively: Add commandline parameter for the reference CA to master cmd
• Implement connection check in the deployer/MSP and generate appropriate probelms
• Implement client cert check in the slave
• Document procedure in the manual (see Add user manual/install instructions #33)

[problame]

remove hardcoded endpoints

[janisstreib]

Slave verification by master done with 444519b

[janisstreib]

Implemented cert auth in 837f43b