Allow configuration of `vendor`

[jclark]

At the moment we have an nmeaNumbering configuration option is the GPS section of satpulsed, which takes the name of a vendor/manufacturer.

This issue proposes to rename this to vendor and also add a --vendor option to satpulsetool. The value of this option would be passed to the gpsreg module.

Initially, the behaviour would be exactly as now: it would call SetNMEANumbering on the NMEA packet processor.

But in the future we can extend it to allow gpsreg to use the vendor in constructing collections of PacketFormats, PacketProcessors and ConfigProtocols. For example, if the user specifies a vendor of u-blox, there is no point in enabling the various unicore specific implementations of these interfaces, because there is no possibility of a u-blox processor emitting any of these packets.

An unspecified vendor would be OK, and would result in an empty string being passed, which would enable all available implementations of these interfaces.

It could also enable vendor-specific tweaks to the constructed implementations, similar to current NMEA numbering.

[jclark]

We would want to match vendor names intelligently: at least case-insensitive, probably also strip hyphens.

[jclark]

This would reduce the need for #130.

[jclark]

The names of vendors used here should line up with what satpulsetool gps reports as the vendor. This means the string constants for these should be defined in the vendor-specific directories.

[jclark]

Note this is not a simple 1-1 mapping. For example:

• RTCM and NMEA would be enabled whatever the vendor, because they are vendor-independent
• novatel PacketFormat and PacketProcessor should be enabled if the vendor is "unicore" (but could pass a flag to handle the slightly different treatment of CPUIdle %ge in the binary packet header)
• vendor of "ByNav" would enable "novatel" packet processor

[jclark]

Tentative list of vendors:

1. u-blox
2. Unicore
3. Bynav
4. Allystar
5. SinoGNSS
6. Quectel
7. NovAtel
8. MediaTek
9. Septentrio
10. Trimble
11. Furuno
12. SkyTraq

[jclark]

We should do the rename early since it is a backwards incompatible change.