Cleanup Emitter helper functions in language repos

[maririos]

The main 4 repos have the following common functions in the Language-Settings.ps1 file. As part of cleaning previous tooling, we should delete these functions.

These are only used by the https://github.com/Azure/azure-sdk-tools/blob/main/eng/common/scripts/TypeSpec-Project-Generate.ps1

.NET:

function Get-dotnet-EmitterName() {
  return "@azure-tools/typespec-csharp"
}

function Get-dotnet-EmitterAdditionalOptions([string]$projectDirectory) {
  return "--option @azure-tools/typespec-csharp.emitter-output-dir=$projectDirectory/src"
}

Java:

function Get-java-EmitterName() {
  return "@azure-tools/typespec-java"
}

function Get-java-EmitterAdditionalOptions([string]$projectDirectory) {
  return "--option @azure-tools/typespec-java.emitter-output-dir=$projectDirectory/"
}

Python

function Get-python-EmitterName() {
  return "@azure-tools/typespec-python"
}

function Get-python-EmitterAdditionalOptions([string]$projectDirectory) {
  return "--option @azure-tools/typespec-python.emitter-output-dir=$projectDirectory/"
}

JS

function Get-javascript-EmitterName() {
  return "@azure-tools/typespec-ts"
}

function Get-javascript-EmitterAdditionalOptions([string]$projectDirectory) {
  return "--option @azure-tools/typespec-ts.emitter-output-dir=$projectDirectory/"
}