Ups this won't work because exports are exported only to lower scripts
not back up so it can't be in separate file.

This implements support for new updater with relative URI and no model
variable.

Upstream prefers to use pip to install dependencies to build_dir instead
of global host directory. That means that these patches are not going to
be upstreamed and we replaced them with upstream suggester approach.

Build server using mirror has invalid HEAD for some reason. Let's for
now set explicit master.

Master is default branch so we do not need it there.

This patch should fix support for Turris 1.x switch and also updates
Turris 1.x to kernel 4.19.

Master is based on lastest development so it should always be the future
version. Currently that is 5.0. This marks it as that.

Upstream should merge this soon so we are going to drop this patch in
suchy case.

OpenWrt decided to enable them in kernel config instead of packaging
them and probably we will need to upstream to OpenWrt
kmod-crypto-marvell-cesa

Source:
https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=f849c2c83247340d623fdb549e2b75f4c1feea62

This reverts commit c165556d.

This patch causes problems with compilation. It was reported to upstream
and let's hope that they are going to fix it.

We are not using them at the moment and we always can investigate git
history to add them back.

This should make much more clearer what are usable and what are not
configuration options.

When branch is provided to feed with `;` we should also replace that
with exact hash.

This fixes problem with ignored packages that were introduced by patch.
What this does is that it installs packages after patching is done. It
also first updates indexes again before installation.

Because this feature was originally split between two function but
patch_feeds had to be inserted to the middle of get_feeds I decided to
drop both and used upper repatch_feeds instead. This means that we are
no longer able to get and patch feeds separately but I think that this
separation was almost useless.

Currently we support Turris OS only with SD card on BTRFS so we should
reflect that here.