Refactor HomePage buttons into ButtonLinks to improve accessibility

[lukaw3d]

Fixes issues:

• Keyboard navigating through these buttons would first focus on the link, and then on the button
• Multiple buttons were marked as type="submit" without being in multiple forms
• On a small screen "Mnemonic / Private key / Ledger" buttons would collapse into rows of left-aligned buttons, but links would fill up the whole row

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ EDITORCONFIG	editorconfig-checker	7		0	0.02s
✅ REPOSITORY	checkov	yes		no	12.91s
✅ REPOSITORY	git_diff	yes		no	0.0s
✅ TSX	eslint	3	0	0	6.51s
✅ TYPESCRIPT	eslint	4	0	0	6.16s

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[buberdds]

This throws tons of console warnings, because props are assigned to HTML attributes. HTML markup is also wrong theme="[object Object]"

[lukaw3d]

🤦 thanks grommet documentation https://v2.grommet.io/button#as

[buberdds]

findByRole('link') in cypress tests

[codecov]

Codecov Report

Merging #1097 (df65e68) into master (9b0813c) will increase coverage by 0.01%.
The diff coverage is 100.00%.

❗ Current head df65e68 differs from pull request most recent head 79bf913. Consider uploading reports for the commit 79bf913 to get more accurate results

@@            Coverage Diff             @@
##           master    #1097      +/-   ##
==========================================
+ Coverage   88.75%   88.77%   +0.01%     
==========================================
  Files         102      103       +1     
  Lines        1778     1781       +3     
  Branches      411      411              
==========================================
+ Hits         1578     1581       +3     
  Misses        200      200              

Flag	Coverage Δ
cypress	60.64% <100.00%> (+0.06%)	⬆️
jest	78.78% <33.33%> (-0.08%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/app/pages/HomePage/index.tsx	100.00% <ø> (ø)
src/app/pages/OpenWalletPage/index.tsx	100.00% <ø> (ø)
src/app/components/ButtonLink/index.tsx	100.00% <100.00%> (ø)

[csillag]

Reviewed. LGTM.