[RFC] Renaming API for consistency

[kodai3]

Summary 💡

API which stands for it's component shape is not consistent between components.
like round vs circle, rectangle vs rect, and outlined (adjective) vs round (noun).

This have been discussed on several PRs by @oliviertassinari and @mblodorn
#18116 (comment)
#21903 (comment)

As this is breaking changes, it would be great to have more feedback from community on suggested changes bellow.

Changes

suggested change by @oliviertassinari at #21903 (comment)

- Pagination (& Item): `shape: PropTypes.oneOf(['round', 'rounded']),`
- Fab: `variant: PropTypes.oneOf(['extended', 'round']),`
- Avatar: `variant: PropTypes.oneOf(['circle', 'rounded', 'square']),`
- Badge: `overlap: PropTypes.oneOf(['circle', 'rectangle']),`
- Skeleton: `variant: PropTypes.oneOf(['circle', 'rect', 'text']),`
+ Pagination (& Item): `shape: PropTypes.oneOf(['circular', 'rounded']),`
+ Fab: `variant: PropTypes.oneOf(['extended', 'circular']),`
+ Avatar: `variant: PropTypes.oneOf(['circular', 'rounded', 'square']),`
+ Badge: `overlap: PropTypes.oneOf(['circular', 'rectangular']),`
+ Skeleton: `variant: PropTypes.oneOf(['circular', 'rectangular', 'text']),`

Related

#20012 (v5 RFC)
#21903
#21593 (loading vs pending)

cc @mui-org/core-team

[oliviertassinari]

@kodai3 I think that we are clear to go on this one.

[kodai3]

I renamed Fab component here #21903.
I will work on the others soon, but anyone can take👌