Add ManiVault variant map for serialization

[ThomasKroes]

PR features

• Adds mv::VariantMap for use in serialization functions (to have ultimate control over how data is serialized)
• Use it in WidgetAction::fromVariantMap(...) and WidgetAction::toVariantMap()
• Write a script to replace QVariantMap to mv::VariantMap when needed and some additional replacements
• Add suffix the ManiVault version printed in the console

Note for plugin developers

Below is a PowerShell script to perform all the necessary replacements in serialization API calls:

# Check if the directory argument is provided
if ($args.Length -lt 1) {
    Write-Host "Usage: replace_mv_variant.ps1 <directory>"
    exit 1
}

# Get the directory from the command-line arguments
$directory = $args[0]

# Validate the directory
if (-not (Test-Path -Path $directory -PathType Container)) {
    Write-Host "Error: Directory '$directory' does not exist."
    exit 1
}

# Define an array of regular expression patterns with corresponding replacement patterns
$patterns = @(
    @{Pattern = "(?:virtual\s*)?(void\s*fromVariantMap\(const\s*)(QVariantMap)(&\s*variantMap\)\s*(?:override)?)"; Replacement = '$1mv::VariantMap$3'},
    @{Pattern = "(?:virtual\s*)?(QVariantMap)(\s*toVariantMap\(\)\s*const\s*(?:override)?)"; Replacement = 'mv::VariantMap$2'},
	@{Pattern = "(void\s*\w+::fromVariantMap\s*\(\s*const\s*)(QVariantMap)(&\s*variantMap\))"; Replacement = '$1mv::VariantMap$3'},
	@{Pattern = "(QVariantMap)(\s*\w+::toVariantMap\(\)\s*const)"; Replacement = 'mv::VariantMap$2'},
	@{Pattern = "(QVariantMap)(\s*variantMap\s*=\s*\w+::toVariantMap\(\))"; Replacement = 'auto$2'}
)

# Get a list of files in the directory and its subdirectories
Get-ChildItem -Path $directory -File -Recurse | ForEach-Object {
	Write-Host "Processing file: $($_.Name)"
	
	# Read the content of each file
    $content = Get-Content $_.FullName
		
	# Perform each replacement using regular expressions and match groups
	foreach ($pattern in $patterns) {
        $newContent = $content -replace $pattern.Pattern, $pattern.Replacement
        $content 	= $newContent
    }
	
	# Write the modified content back to the file
    $content | Set-Content $_.FullName
}

To run the script:
.\replace_mv_variant_map.ps1 .\DevBundle\allmain\source\ImageViewerPlugin\src\