Change apt's default compression method to gzip

[lurdan]

Description

APT uses lz4 as its default compression method, but Some ARM board has performance problem on it.
This setting make apt prefer gzip over lz4.

cf. https://forum.armbian.com/topic/14064-my-apt-search-has-become-super-slow-recently/page/2/

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• Test A
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Checklist:

• My code follows the style guidelines of this project
• [X ] I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[token0]

@igorpecovnik I suggest to make an option in armbian-config to select lz4 or gz. Making gz default everywhere is a bad idea. In my case I made a backup script with preferred lz4 and failover to gz.

@lurdan about this issue (5a14a43)
I had this ultra slow search problem too, until I disabled apt incremental (delta) updates and disabled ipv6 for apt (to increase sync speed in my case). I'm running armbian on rk3328. Also performance increased significantly when I moved my system from SD card to Samsung Bar Plus USB 3.1 drive — it has outstanding performance on small blocks, and also rare kernel panics were gone (blame old SD card).
PS: You could try to search with aptitude instead of apt.

[lurdan]

@token0
I agree with setting gzip as default is rather dirty hack, though I have no idea how users can avoid hitting lz4 slowness.
Maybe users who know what makes their apt slow will find the armbian-config option...

Anyway, I don't care reverting this or overwriting with better fix.