Feature/#1127 dynamic suggested fee

[ARR552]

Closes #1127

What does this PR does?

This PR enable the dynamic suggested fee. The suggested fee changes depending on the ethereum gas fee used in the network. Also, this PR fixes the bug related to logger in configuration

Data verification performed using https://github.com/hermeznetwork/TestDynamicFeesService

How to test?

Run hermez node using PolicyType = "AvgLastHourResizable"

Checklist

These are the criteria that every PR should meet, please check them off as you review them:

• [x] Include tests
• [X] Respect code style and lint
• [ ] Update swagger file (if needed)
• [X] Update documentation (*.md) (if needed)