MT#5811 Properly set websocket paths.

To work around ssl certificate issues with wss connections, use
a single entry point for wss to the system and let nginx do the
internal proxying to the correct addresses.
MT#5835 Spanish translation update
MT#5835 Spanish translation update
MT#5835 Spanish translation update
MT#5835 Update spanish datatables translations.
MT#5083 Add webfax to subscriber top menu
MT#3933 API: add subscriber editing via PUT/PATCH
MT#5835 Translate javascript datatables file to Spanish.
MT#5837 Add Russian localisation

Many tnx to Andrew Pogrebennyk!
MT#5837 Unify some terms; improve subscriber details look.
MT#3925 Return json error for 403/404 on /api/.+

Return as usual a json struct with code and message under the /api/ path.
Otherwise an API client would get the html pages, which is
pretty pointless.
MT#3933 API: Implement subscriber preferences.

While at it, combine preference handling for subscribers, domains
and peers into a single role.
MT#5835 Fixed Spanish datatables translations.
MT#5967 Perform trusted source ip/net validation.
MT#5835 Spanish translation update
MT#5967 Validate (man_)allowed_ip input.

Check for valid v4/v6 address and optional netmask.
MT#5811 Prepare adding chat buddy.
MT#3933 API: Handle subscriber lock/termination
MT#5967 API: validate allowed ip entries.
Merge remote-tracking branch 'origin' into ipeshinskaya/InvoiceTemplate2