Add editor limit hit blocking

[varmar05]

This is CE part for integration of new editor limit hit blocking mechanism. PR adds:

• a new error type
• a revert mechanism for updates that were rejected

[coveralls]

Pull Request Test Coverage Report for Build 12318536813

Details

• 5 of 11 (45.45%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.08%) to 93.406%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
server/mergin/sync/public_api_controller.py	5	11	45.45%

Totals
Change from base Build 12276007973:	-0.08%
Covered Lines:	6587
Relevant Lines:	7052

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💛 - Coveralls