phoss SMP 5.0.3

• Initial support for SMP Docker images was added
• Fixed NPE in REST API if an invalid data format was used
• Made SML registration IP and hostname configurable (see issue #49)
• Existing service groups can now be subsequently registered to the SML (see issue #51)
• The "SML registration" pages now contains a note, if the SMP is already registered to the SML.
• The default page of the PEPPOL Directory was changed to https://directory.peppol.eu - because of the very special https setup currently used, an update to the PD client library v0.5.1 is highly recommended
• An error prevented Business Cards from being imported correctly - Thanks Ger for pointing this out
• An exception when using the PEPPOL REST API in combination with an Endpoint without an URI was fixed
• The Docker image got vim by default (see issue #45)