PatternFly React: Our own FormFieldset and FormLegend components

[didierofrivia]

What this PR does / why we need it:

the patternfly-react lib hasn't implemented still the components for fieldset and legend, so these ones are the ones we will be using until they release their own.

Needed for #1315
Which issue(s) this PR fixes

Verification steps

Special notes for your reviewer:
These components will be removed when patternfly team release the official ones.

[codecov]

Codecov Report

Merging #1339 into master will decrease coverage by 2.4%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1339      +/-   ##
==========================================
- Coverage   93.17%   90.76%   -2.41%     
==========================================
  Files        2518     2216     -302     
  Lines       83583    68940   -14643     
==========================================
- Hits        77877    62574   -15303     
- Misses       5706     6366     +660

Impacted Files	Coverage Δ
.../initializers/backport_pg_10_support_to_rails_4.rb	30% <0%> (-50%)	⬇️
config/initializers/postgres.rb	50% <0%> (-50%)	⬇️
..._portal/admin/account/braintree_blue_controller.rb	51.61% <0%> (-41.94%)	⬇️
...developer_portal/admin/account/ogone_controller.rb	62.5% <0%> (-37.5%)	⬇️
...ib/developer_portal/lib/liquid/drops/pagination.rb	54.76% <0%> (-36.91%)	⬇️
...ortal/admin/account/personal_details_controller.rb	57.14% <0%> (-25.72%)	⬇️
...veloper_portal/admin/messages/outbox_controller.rb	50% <0%> (-25%)	⬇️
lib/developer_portal/lib/liquid/drops/menu.rb	76.92% <0%> (-23.08%)	⬇️
config/initializers/access_token_authentication.rb	55.55% <0%> (-22.23%)	⬇️
lib/developer_portal/lib/liquid/drops/i18n.rb	82.6% <0%> (-17.4%)	⬇️
... and 310 more

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[damianpm]

Approving, just leave some comments but totally optional, would like to see it in action

[damianpm]

There is a PF Label component, we could use that to not rewrite already existing components.
But I think it will be lighter and simpler using only a vanilla <label> tag here, considering this is a temporary solution until core PF team develops the <Fieldset /> component. So it's OK for me

[didierofrivia]

Funny thing is they use the exactly samelabel composition for their FormGroup component and not the Label component.

[damianpm]

Do you know if is there an open issue or PR created for this? May be useful to have it, to track progress

[didierofrivia]

Nope, not a single thing. Also, I didn't open one because they don't have it in their library pattern for v4 nor v3 (following they contribution guidelines). I've asked about this in their slack, but no answer.