Module transactions are not decoded properly

[tschubotz]

Problem summary

It is currently no possible to view module txs on a Safe in some human readable format.

Problem details

• After a Safe enabled a module and that module made a tx, it is displayed as a module tx in the tx list.
• No further info is given about which module is was.
• There is only limited custom decoding for the spending limits module.

Solution ideas

• Display the module address on the tx details (and link to Etherscan)
• Use know addresses for module address.
• Ensure that module txs are decoded nicely.