Replace occurences of ar71xx with ath79. Remove references of ar71xx
targets which are not relevant anymore.

I mixed up two separate improvements into one, this change aims to
clarify them based on a suggestion and conversation with @T-X.

Explains the behaviour when DATE is either in the future or in the past
and hints at how the firmware rollout can be controlled using the
PRIORITY variable.

Co-Authored-By: Martin Weinelt <martin@darmstadt.freifunk.net>

Co-Authored-By: Martin Weinelt <martin@darmstadt.freifunk.net>

This device is a dual 5GHz device. It is recommended to manually change the
radio of the first device to the lower 5GHz channels and the second radio
to the upper 5GHz channels

The map is generated from EUMETNET data, it's source code can be
found at https://gitlab.com/aaaaalbert/wxr-channel-map.

* ar71xx-generic: only create manifest alias for Rocket M5

This follow up the discussion done in #2070 by not  creating a symlink
for the Rocket M5. Images for the Rocket M2 can still be flashed on a
Rocket M5.

This change will prevent the Rocket M5 from appearing in Firmware
selectors. Existing devices will still receive updates, as the device
name is still referenced for the device name expected by the M5.

Closes #2070

* docs: remove Rocket M5 from supported devices

Fixes #2113

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>

The rewrite of the feature handling introduced multiple major bugs. One
of them was caused by the way Lua's logical operators work:

An expression of the form

    _'autoupdater' and _'web-advanced'

would return 'web-advanced' rather than the boolean true when _ returned
both strings unchanged (because the features are enabled).

As entries with more than a single feature name in their expressions did
not set no_default, Gluon would then attempt to add gluon-web-advanced to
the package selection, as web-advanced is a "pure" feature.

To fix this, and get rid of the annoying nodefault, separate handling of
"pure" feature and handling of logical expressions into two separate
functions, called feature() and when(). To simplify the feature
definitions, the package list is now passed directly to these functions
rather than in a table with a single field 'packages'.

Fixes: ee5ec5af ("build: rewrite features.sh in Lua")

Fix a number of issues related to the vertical alignment and margins of
list elements.

(cherry picked from commit bf8c3bab)

Closes #1979
Closes #2062

(cherry picked from commit 582d2d69)

Closes #1979
Closes #2062

Document the behavior of the Outdoor mode when preserve_channels is
enabled.

Document the behavior of the Outdoor mode when preserve_channels is
enabled.

Allow replacing the default OSM layer with a custom XYZ layer in
site.conf.

The `features` file is converted to a Lua-based DSL.

A helper function `_` is used in the DSL; this will return the original
string for enabled features, and nil for disabled features. This allows
to use boolean operations on features without making the code too
verbose.

Besides having more readable and robust code, this also fixes the bug
that all files `packages/*/features` were evaluated instead of only
using the feature definitions of currently active feeds.