Configuration concept

Basically, we have two different categories of configuration parameters: Parameters directly related to the HNAP waveform and parameters which are related to the Pluto Linux system.
The basic system and network settings are originally handled within uboot's fw environment and presentet to the user by the config.txt file which is also accessible by the USB mass storage.
We'll not cancel this concept to avoid confusion. Therefore, our current decision is to provide the HNAP relevant settings in the hnap_config.txt and add our additional system related settings (network configuration) in the fw environment/config.txt as well.

## Examples for HNAP Waveform Configuration parameters:

- Loglevel
- Frequency
- Tx gain
- Desired MCS
- PTT Offset
...

## Examples for Pluto System Configuration parameters:

- Hostname
- Callsign
- Network settings (TAP IP, Subnet)
- DHCP Server configuration
- ...

## To Dos

- [x] the HNAP config file will be renamed to hnap_config.txt to avoid confusion with the Pluto config.txt file
- [x] the HNAP config file will be stored to the jffs2 partition to enable persistence
- [ ] we'll add the Tx and Rx gain setting to the HNAP config file
- [ ] basestation autostart will read the config file instead of having hard-coded parameters (related to #54)
- [ ] define relevant parameters to set up various networking scenarios