Remove a lot of redundant code by switching to a match table listing
the targets and boards for each candidate for the primary MAC interface.

In addition, we add some flexiblity by allow to switch out the sysfs file
data source for the MAC address.

Allow wildcard matches on all subtargets of a target, or a full wildcard
always returning true when no arguments are passed.

Specification:
- MediaTek MT7620A (580 Mhz)
- 64 MB of RAM
- 8 MB of FLASH
- 2T2R 2.4 GHz and 1T1R 5 GHz
- 5x 10/100 Mbps Ethernet
- 2x external, non-detachable antennas
- UART (J1) header on PCB (115200 8n1)
- 8x LED (GPIO-controlled*), 2x button, power input switch
- 1 x USB 2.0 port

This reverts commits
- caf2dd03.
- 07ebac6a
- 55eff45f

I accidentally pushed these commits as I had them lying around on a
dirty checkout I did testing on.

- Split into multiple files
- Avoid alloca()

In addition this PR contains:
- split of gluon-respondd provider into multiple source files
- minor additional cleanups in gluon-mesh-babel respondd provider
  (untested, as the babel respondd provider already doesn't compile prior
  to these changes...)

While we're at it, also slightly optimize proto_gluon_bat0_renew.

Adjust for changed libbabelhelper API.

We don't use anything else from luci-base anymore.

The code is slightly cleaned up to fix compiler warnings.

We don't support VLANs on 11s interfaces, so the workaround can be dropped
with the IBSS support.

many AVM devices do not have RESET/WPS buttons. So use the otherwise unused DECT/PHONE button to boot the device into setup mode.

This patch allows to enter the setup-mode by pressing the phone button
(often labeled as DECT) in addition to WPS and reset button.

This patch is necessary to allow supporting boards without a WPS and reset
button (e.g. AVM FRITZ!Box 7312).

Fixes: 4249d65a ("treewide: fix luacheck warnings")
Closes: #1851

This commit accounts for the target renaming which was done in upstream
commit 7407e723991 ("ipqx0xx: add Generic subtarget")

This commit accounts for the target renaming which was done in upstream
commit 7407e723991 ("ipqx0xx: add Generic subtarget")

With this commit, the status-led is set to be the "led-running"
device-tree alias for targets which do not implement the get_status_led
method in /etc/diag.sh.