[gbs] Let tizen gbs build use cache properly

[anyj0527]

• Currently only the first arch option use the gbs build cache.
• Remove GBS-ROOT folder when all the tizen gbs build is finished.
• Expecting quite a time boost on gbs build tasks by removing rpm downloading.

Self evaluation:

1. Build test: [ ]Passed [ ]Failed [ ]Skipped
2. Run test: [X]Passed [ ]Failed [ ] Skipped

[taos-ci]

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[taos-ci]

@anyj0527, 💯 All CI checkers are successfully verified. Thanks.

[myungjoo]

Can you remove GBS-ROOT conditionally? (e.g., the first check of a day or 10% probability or explicit input from users via webhook? ...)

[myungjoo]

Can you remove GBS-ROOT conditionally? (e.g., the first check of a day or 10% probability or explicit input from users via webhook? ...)

[anyj0527]

@myungjoo
Well currently the GBS-ROOT is created per PR with global gbs repo cache. I'm not sure that sharing GBS-ROOT among multiple PRs would be more effective.