Adding support for executing transactions in scripting mode

[falvaradorodriguez]

Closes #36

Points of interest:

• Added send_ether, send-erc20, send-erc721, send-custom and tx-builder commands. The first commands allow to execute transactions and the second, by importing a file generated by the tx_builder, can execute tx batches using the MultiSendCallOnly contract.
• The logic of the tx_builder_file_decoder is developed based on what I know is done in the front end tx_builder. Added here: Add support for executing transactions from tx-builder json file #426
• A script_mode no_input property is added to safe_operator to raise exceptions that terminate execution instead of just displaying the error message (prompt mode).
• Updated the Readme file with the examples of the added commands.

[coveralls]

coverage: 88.843% (+1.6%) from 87.279%
when pulling 8d82f8a on support_scripting
into dbea553 on main.

[coveralls]

coverage: 88.804% (+1.5%) from 87.279%
when pulling ee7a27c on support_scripting
into dbea553 on main.

[coveralls]

coverage: 88.812% (+1.5%) from 87.279%
when pulling 1e1d354 on support_scripting
into dbea553 on main.

[coveralls]

coverage: 87.771% (+0.5%) from 87.279%
when pulling d8319c9 on support_scripting
into f84bc0e on main.

[coveralls]

coverage: 87.771% (+0.5%) from 87.279%
when pulling 040622f on support_scripting
into d9ac0c1 on main.

[fmrsabino]

Great job 👏

I was considered additionally that the purpose of this PR, in addition to the "attended-mode" was to support scripting. In that case I think having a --no-input flag or similar should be added (initially to the commands that require it but in the future for it to be a global parameter).

[coveralls]

coverage: 87.46% (+0.2%) from 87.279%
when pulling f9b5250 on support_scripting
into d9ac0c1 on main.

[coveralls]

coverage: 87.47% (+0.2%) from 87.279%
when pulling da2c9ae on support_scripting
into a9427b2 on main.

[coveralls]

coverage: 87.47% (+0.2%) from 87.279%
when pulling da2c9ae on support_scripting
into a9427b2 on main.

[fmrsabino]

Great work 👏 👏 👏