[Quagga] Remove Quagga from SONiC

[liorghub]

Why I did it

Quagga is no longer being used in SONiC.

Cherry-pick from master PR #7898

How I did it

Remove Quagga git submodule and related code.

How to verify it

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[lgtm-com]

This pull request fixes 2 alerts when merging 89d0f08 into 308ecbb - view on LGTM.com

fixed alerts:

• 2 for Unused import

[liat-grozovik]

@liorghub can you please refer in the PR description to the original PR from master used as a base for this PR?

[liat-grozovik]

@prsunny , @xumia could you please check the build failures?

It seems that some has a infra issue. For example:
"System.UnauthorizedAccessException: Access to the path '/agent/_work/1/s/platform/vs/tests/log/test_default_route/log/wtmp' is denied."

[xumia]

@prsunny , @xumia could you please check the build failures?

It seems that some has a infra issue. For example: "System.UnauthorizedAccessException: Access to the path '/agent/_work/1/s/platform/vs/tests/log/test_default_route/log/wtmp' is denied."

It should be an azp agent issue, please retry it.