memoryLimit: redefine to not include swap

Currently, we allocate 50% as RAM and 50% as swap. The manifest is
usually quite conservative on memory values. This means that we set
up a system where the app is applying memory pressure almost immediately.
This then swaps things randomly and increases cpu usage (kswapd shows
up in the profile).

To rethink the whole situation: we should not cap apps with a swap limit at all.
The memory hard limit is what is important. By redefining memoryLimit , we are
doubling every container's memory and it's good that we over allocate this.

src/mailserver.js

@@ -45,7 +45,6 @@ const assert = require('assert'),
     services = require('./services.js'),
     settings = require('./settings.js'),
     shell = require('./shell.js'),
-    system = require('./system.js'),
     tasks = require('./tasks.js'),
     users = require('./users.js');
 
@@ -145,7 +144,6 @@ async function configureMail(mailFqdn, mailDomain, serviceConfig) {
 
     const image = infra.images.mail;
     const memoryLimit = serviceConfig.memoryLimit || exports.DEFAULT_MEMORY_LIMIT;
-    const memory = await system.getMemoryAllocation(memoryLimit);
     const cloudronToken = hat(8 * 128), relayToken = hat(8 * 128);
 
     const certificate = await reverseProxy.getMailCertificate();
@@ -182,8 +180,8 @@ async function configureMail(mailFqdn, mailDomain, serviceConfig) {
                 --log-opt syslog-address=unix://${paths.SYSLOG_SOCKET_FILE} \
                 --log-opt syslog-format=rfc5424 \
                 --log-opt tag=mail \
-                -m ${memory} \
-                --memory-swap ${memoryLimit} \
+                -m ${memoryLimit} \
+                --memory-swap -1 \
                 --dns 172.18.0.1 \
                 --dns-search=. \
                 -e CLOUDRON_MAIL_TOKEN=${cloudronToken} \