Merge the develop branch to the master branch, preparation to v2.0.0-rc0

[akolotov]

This merge contains the following set:

• [Improvement] Use 3 validators in oracle e2e tests (Use 3 validators in oracle e2e tests #264), closes Use 3 validators for e2e testing of the oracle #63
• [Improvement] Updated oracle watchers to use blob version of execute signatures (Updated oracle watchers to use blob version of execute signatures #269), closes Unify collected signatures sending #267
• [Improvement] Add deployment test scenario 3 components on 1 host (Add deployment test scenario 3 components on 1 host #277), closes Add tests covering a scenario where 3 components are deployed on 1 host #209 , closes the monitor is not deployed properly on the system with oracle  #273
• [Improvement] Add ultimate e2e tests for AMB (Add ultimate e2e tests for AMB #285), closes ultimate e2e tests for AMB #217
• [Improvement] Use oracle docker hub image for oracle deployment (Use oracle docker hub image for oracle deployment #280), closes Use the images from the docker hub for the oracle deployment #268
• [Improvement] Use monitor docker hub image for monitor deployment (Use monitor docker hub image for monitor deployment #284), closes Use the images from the docker hub for the monitor deployment #274
• [Fix] Fix remote server loop var name in deployment (Fix warning in logging configuration in deployment #275), closes Logging by syslog enabled only for one service #270
• [Fix] Add custom response for favicon resource in monitor (Add custom response for favicon resource in monitor #278), closes ERROR produced by monitor's web service during favicon.ico lookup #271
• [Fix] Update monitor check-all script to generate stuckTransfers statistics for v1 bridges (Update monitor check-all script to generate statistics for 1.x bridges #279), closes Cannot have monitor for 1.x and for 2.x bridge contracts on the same node #272
• [Other] Update the contract's submodule to the release 4.0.0-rc0 (Update the contract's submodule to the release 4.0.0-rc0 #276)