Menu component: Let consumer add SearchInput/TextInput and remove hasSearchInput prop

Copying from conversation with @karelhala, @jenny-s51 and @mcoker in slack:

While I was going trough the component itself I think it could be improved, I don’t think we need to include the hasSearchInput prop at all, we could allow passing custom components as consumers require, here is an example - https://codesandbox.io/s/cocky-yonath-65nuf?file=/index.js

we could provide more components to control that level, i.e. by adding a MenuInput and MenuContent container

<Menu>
  <MenuInput>
    <SearchInput />
  </MenuInput>
  <Divider>
  <MenuContent>
    <MenuList>
      <MenuListItem />
      <MenuListItem />
    </MenuList>
  </MenuContent>
</Menu>

Related: https://github.com/patternfly/patternfly-react/issues/5153

[mcoker]

Technically you can, there are no styles associated with <MenuGroup> or <MenuContent>. They’re just used for sectioning.

cc @mcarrano

[tlabaj]

closed by #5211