Rename QoS policy manager to DSCP manager to avoid confusion

[mazdakn]

Description

Rename qos to dscp in file names, variables, types, etc made in the following two PRs, to avoid confusion as feature is all about setting DSCP:

• Set DSCP for workload's egress traffic leaving cluster #10718
• Set DSCP for host endpoints #10825

Related issues/PRs

Todos

• Tests
• Documentation
• Release note

Release Note

TBD

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[Copilot]

Pull Request Overview

This PR renames QoS policy manager to DSCP manager to better reflect the feature's purpose of setting Differentiated Services Code Point (DSCP) values rather than generic Quality of Service policies.

• Renames types, variables, and functions from "qos"/"QoS" to "dscp"/"DSCP" throughout the codebase
• Updates chain names and test descriptions to reflect the more specific DSCP functionality
• Maintains the same functionality while providing clearer naming conventions

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
felix/rules/static_test.go	Updates test expectations to use new DSCP chain name
felix/rules/static.go	Changes chain target from QoS policy to egress DSCP
felix/rules/rule_defs.go	Renames chain constant and method signature from QoS to DSCP
felix/rules/dscp_test.go	Updates test descriptions and variable names from QoS to DSCP
felix/rules/dscp.go	Renames type and method from QoSPolicy to DSCPRule with updated field names
felix/fv/dscp_test.go	Updates functional test descriptions and chain name references
felix/dataplane/linux/int_dataplane.go	Changes manager instantiation from QoS policy to DSCP manager
felix/dataplane/linux/dscp_mgr_test.go	Updates test descriptions and variable names throughout
felix/dataplane/linux/dscp_mgr.go	Renames manager type and updates all QoS references to DSCP