Add `node_url` instead of `node_ip` and `node_port` in oracle config

[greenhat]

Close #205

[coveralls]

Pull Request Test Coverage Report for Build 3874075361

• 0 of 97 (0.0%) changed or added relevant lines in 15 files are covered.
• 16 unchanged lines in 10 files lost coverage.
• Overall coverage increased (+0.5%) to 62.238%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
core/src/oracle_config.rs	0	1	0.0%
core/src/node_interface.rs	0	2	0.0%
core/src/pool_commands/test_utils.rs	0	2	0.0%
core/src/cli_commands/vote_update_pool.rs	0	3	0.0%
core/src/api.rs	0	4	0.0%
core/src/cli_commands/transfer_oracle_token.rs	0	4	0.0%
core/src/cli_commands/update_pool.rs	0	4	0.0%
core/src/scans.rs	0	4	0.0%
core/src/cli_commands/extract_reward_tokens.rs	0	5	0.0%
core/src/cli_commands/bootstrap.rs	0	6	0.0%
<!--	Total:	0	97	0.0%	-->

Files with Coverage Reduction	New Missed Lines	%
core/src/api.rs	1	0%
core/src/cli_commands/extract_reward_tokens.rs	1	59.68%
core/src/cli_commands/prepare_update.rs	1	67.19%
core/src/node_interface.rs	1	0%
core/src/oracle_state.rs	1	0%
core/src/cli_commands/bootstrap.rs	2	86.97%
core/src/cli_commands/transfer_oracle_token.rs	2	53.7%
core/src/cli_commands/update_pool.rs	2	58.02%
core/src/scans.rs	2	0%
core/src/cli_commands/vote_update_pool.rs	3	63.1%
<!--	Total:	16		-->

Totals
Change from base Build 3853119037:	0.5%
Covered Lines:	1963
Relevant Lines:	3154

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💛 - Coveralls