Add token address in asset list

[iamacook]

What it solves

Resolves #2966

How this PR fixes it

A button which opens Etherscan (or the relevant block explorer) to the token address was added next to the token name.

How to test it

1. Open a safe with varying assets.
2. Click the button that opens the block explorer.
3. Verify that it is correct.

Screenshots

[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

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^{Report generated by eslint-plus-action}

[coveralls]

Pull Request Test Coverage Report for Build 1531381042

• 0 of 3 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 32.733%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/routes/safe/components/Balances/AssetTableCell/index.tsx	0	3	0.0%

Totals
Change from base Build 1530175501:	0.0%
Covered Lines:	3110
Relevant Lines:	8466

---

💛 - Coveralls

[github-actions]

Deployment links

🟠 Safe Rinkeby	⚪ Safe Mainnet	🟣 Safe Polygon	🟡 Safe BSC	⚫ Safe Arbitrum	🟢 Safe xDai

[github-actions]

E2E Tests Failed
Check the results here: https://github.com/gnosis/safe-react-e2e-tests/actions/runs/1531420679

Failed tests:

• ❌ Address book Address book
• ❌ Safe Apps List Safe Apps List
• ❌ Read-only transaction creation and review Create and review a Send Funds transaction

[katspaugh]

You're a productivity monster, Aaron! 💚

[katspaugh]

Tested on mainnet and Polygon, works correctly for both native coins and other tokens. ✅

[francovenica]

Looks good to me
Tested in all networks with some tokens I had in different safes.
Mainnet: 0x8675B754342754A30A2AeF474D114d8460bca19b
Rinkeby: 0x9913B9180C20C6b0F21B6480c84422F6ebc4B808
xdai: 0xB8d760a90a5ed54D3c2b3EFC231277e99188642A
Poly: 0x39A4D23652d40AF13812E1d01C4aF65559Dd6850
Bsc: 0x91e11585c114129f3Ec940Aa648A4ac13668d0c2
EWC: 0x082fcc9f1A997b45395aBf7FD7DEeA2D0Ce68270
Volta: 0x538622a690A651D852277c07334dC3377E22cdeF
Arb: 0xD62269DB700dF2D274Aca12Ae95AbA3eeB0B0914