Wait for tx confirmation in commands + introduce ExplorerApi

[greenhat]

Close #208 Close #216

[coveralls]

Pull Request Test Coverage Report for Build 3940500459

• 15 of 80 (18.75%) changed or added relevant lines in 10 files are covered.
• 4 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-0.7%) to 61.541%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
core/src/cli_commands/update_pool.rs	0	1	0.0%
core/src/cli_commands/vote_update_pool.rs	0	1	0.0%
core/src/main.rs	0	1	0.0%
core/src/node_interface.rs	0	1	0.0%
core/src/cli_commands.rs	0	2	0.0%
core/src/cli_commands/prepare_update.rs	5	7	71.43%
core/src/cli_commands/bootstrap.rs	10	13	76.92%
core/src/cli_commands/extract_reward_tokens.rs	0	3	0.0%
core/src/cli_commands/transfer_oracle_token.rs	0	3	0.0%
core/src/explorer_api.rs	0	48	0.0%
<!--	Total:	15	80	18.75%	-->

Files with Coverage Reduction	New Missed Lines	%
core/src/cli_commands/extract_reward_tokens.rs	1	58.73%
core/src/cli_commands/transfer_oracle_token.rs	1	52.73%
core/src/cli_commands/update_pool.rs	1	57.58%
core/src/cli_commands/vote_update_pool.rs	1	62.35%
<!--	Total:	4		-->

Totals
Change from base Build 3874770807:	-0.7%
Covered Lines:	1973
Relevant Lines:	3206

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💛 - Coveralls