Component:

<apex:component access="global" controller="orderedLineItems">
    <apex:attribute name="opportunityID" description="This is the ID of the oppotunity." type="ID" assignTo="{!opportunityID}" />
    <!--I suppose you could send over a list of lineItems but this would only really work well with a StandardController as you can pass related Lists but to make
    this work in pages that use custom controllers I am only passing the Opp Id and then I will query for the products -->
    <!--<apex:attribute name="opportunityLineItems" description="List of the OpportunityLineItems." type="OpportunityLineItem[]" />-->
    
    <apex:dataTable value="{!lineItems}" var="l">
        <apex:column value="{!l.pricebookEntry.Name}"/>
        <apex:column value="{!l.Quantity}"/>
        <apex:column value="{!l.UnitPrice}"/>
        <apex:column value="{!l.TotalPrice}"/>
    </apex:dataTable>
</apex:component>


Controller:

public class orderedLineItems {

        public Id opportunityID {get; set;}
        List<OpportunityLineItem> lineItems;
        
        public List<OpportunityLineItem> getlineItems(){
            if(lineItems == null){
                /*Using dyanamic apex and SOQL you could set this up to query all*/
                lineItems = [select Id, PricebookEntry.Name, Quantity, UnitPrice, TotalPrice from OpportunityLineItem where OpportunityID =:opportunityID];
                lineItems = sortLines(lineItems);
            }
            return lineItems;
        }
        
        private static List<OpportunityLineItem> sortLines(List<OpportunityLineItem> olis) {
            List<OpportunityLineItem> resultList = new List<OpportunityLineItem>();
        
            /* Create a map of amount to Opportunity collection */
            Map<String, List<OpportunityLineItem>> oliMap = new Map<String, List<OpportunityLineItem>>();
            
            for(OpportunityLineItem oli : olis) {
                if(oliMap.get(oli.PricebookEntry.Name) == null){ 
                    oliMap.put(oli.PricebookEntry.Name, new List<OpportunityLineItem >()); 
                }
                oliMap.get(oli.PricebookEntry.Name).add(oli);
            }
            
            List<String> keys = new List<String>(oliMap.keySet());
            
            /* Leverage the standard, primitive collection sort method */
            keys.sort();
            
            for(String key:keys){ 
                resultList.addAll(oliMap.get(key)); 
            }
            
            return resultList;
        }
}


VF Email template:

<messaging:emailTemplate subject="Testing" recipientType="Contact" relatedToType="Opportunity">
    <messaging:htmlEmailBody >
        This is your new Visualforce Email Template.<br/>
        
        <c:orderedLineItems opportunityID="{!relatedTo.ID}"/>
   
    </messaging:htmlEmailBody>
</messaging:emailTemplate>