Rename classes with unclear names

[yuto-trd]

Description

• Renamed classes with unclear or ambiguous names to improve code readability and maintainability.
• Moved classes from Beutl.Rendering to Beutl.Graphics.Rendering to eliminate redundancy between the two namespaces.

Breaking changes

• Class names have been updated, which may require changes in files that reference these classes.
• Classes previously in Beutl.Rendering are now located in Beutl.Graphics.Rendering, which may require updates to import statements and references in the code.

Fixed issues

[github-actions[bot]]

Package	Line Rate	Branch Rate	Complexity	Health
Beutl.Extensibility	0%	0%	53	➖
Beutl.Threading	100%	94%	118	✔
Beutl.Core	30%	27%	3015	➖
Beutl.Language	0%	0%	608	➖
Beutl.Configuration	39%	19%	292	➖
Beutl.ProjectSystem	12%	6%	2127	➖
Beutl.Utilities	73%	67%	360	➖
Beutl.Engine	25%	25%	8565	➖
Beutl.Operators	4%	0%	343	➖
Summary	24% (8812 / 36047)	24% (2516 / 10631)	15481	➖

Minimum allowed line rate is 0%