Add dHedge safe app

[dasanra]

Add dHedge safe app

@francovenica This app only works on mainnet. Can be tested using this link:
https://ipfs.io/ipfs/QmaiemnumMaaK9wE1pbMfm3YSBUpcFNgDh3Bf6VZCZq57Q/

[github-actions]

CLA Assistant Lite All Contributors have signed the CLA.

[github-actions]

ESLint Summary View Full Report

Annotations are provided inline on the Files Changed tab. You can also see all annotations that were generated on the annotations page.

Type	Occurrences	Fixable
Errors	0	0
Warnings	0	0
Ignored	0	N/A

• Result: ✅ success
• Annotations: 0 total

---

^{Report generated by eslint-plus-action}

[ghost]

Travis automatic deployment:
https://pr1821--safereact.review.gnosisdev.com/rinkeby/app

[ghost]

Travis automatic deployment:
https://pr1821--safereact.review.gnosisdev.com/volta/app

[francovenica]

Safe and env: https://gnosis-safe.io/app/#/safes/0x8675B754342754A30A2AeF474D114d8460bca19b/transactions

To make this work I took a pool from the dHedge webpage and load it in the app to invest into it
https://app.dhedge.org/pool/0x63ae7457b8be660daaf308a07db6bccb733b92df

Added the app with the link given in the description of the ticket, tried one investment and it worked fine (the tx went through)

Note: I've spent 136dls on this tx, so I won't try another one :D

[ghost]

Travis automatic deployment:
https://pr1821--safereact.review.gnosisdev.com/rinkeby/app