git-lfs: add new package

[ja-pa]

Maintainer: me
Compile tested: Turris Omnia (TOS6), OpenWrt master
Run tested: Turris Omnia (TOS6), OpenWrt master

Description:
This PR adds new package git-lfs. It helps to store large file inside git.

This is related to PR #13919. It is one of the required packages from GitLab to run custom executor https://docs.gitlab.com/runner/executors/custom.html#prerequisite-software-for-running-a-job

[ja-pa]

There is error for x86_64, i386, arm, aarch64

No packages removed.
 * pkg_run_script: Internal error: perlbase-i18n has a NULL tmp_unpack_dir.
 * pkg_run_script: Internal error: perlbase-i18n has a NULL tmp_unpack_dir.
Error: Process completed with exit code 255.

I'm not sure if this is related to git-lfs

[BKPepe]

@jefferyto may I ask you if you can take a look? :)

[jefferyto]

Perhaps unsurprisingly, there are -X ldflags that can be set with GO_PKG_LDFLAGS_X. Otherwise the package looks fine to me.

@aparcar would be the better person to ask regarding the CI errors.

[BKPepe]

@ja-pa Can you please rebase it and take a look at Jeffery's feedback, please?