Fix handling of liquibase fails

In the class ModTenantAPI method "loadData" doesn't pay attention on error messages from liquibase (it gives back "successfully" in any case)

Future<Integer> loadData(TenantAttributes attributes, String tenantId,
Map<String, String> headers, Context context) {

return super.loadData(attributes, tenantId, headers, context)....

Steps to reproduce:

1. rebuild SRS with folio-liquibase-util-1.5.0-SNAPSHOT
2. vagrant up
3. change the value in the "md5sum" field in the "diku_mod_source_record_storage.databasechangelog" table to any value
4. run POST request to SRS:
   for example:

   curl "http://localhost:9177/_/tenant" -H "X-Okapi-Tenant: diku" -H "X-Okapi-URL: http://localhost:9177" -H "Content-type: application/json" -XPOST -d' 
   {
     "module_to": "mod-source-record-storage-5.4.0-SNAPSHOT",
     "parameters": [{
     "key": "loadSample",
     "value": "true"
     },{
     "key": "loadReference",
     "value": "true"
     }]
   }'
   

1. check response

   {
     "id" : "e1b4d15b-8c8b-4eb8-89c2-0bb7675f39c7",
     "tenant" : "diku",
     "tenantAttributes" : {
       "module_to" : "mod-source-record-storage-5.4.0-SNAPSHOT",
       "parameters" : [ {
         "key" : "loadSample",
         "value" : "true"
       }, {
         "key" : "loadReference",
         "value" : "true"
       } ]
     },
     "complete" : false,
     "messages" : [ ]
   }
   

Expected result (see "error message"):

{
  "id" : "95e95b9f-ce3f-4a4f-b453-11b70752c27d",
  "tenant" : "diku",
  "tenantAttributes" : {
    "module_to" : "mod-source-record-storage-5.4.0-SNAPSHOT",
    "parameters" : [ {
      "key" : "loadSample",
      "value" : "true"
    }, {
      "key" : "loadReference",
      "value" : "true"
    } ]
  },
  "complete" : true,
  "error" : "liquibase.exception.ValidationFailedException: Validation Failed:\n     1 change sets check sum\n          liquibase/tenant/scripts/v-5.0.6-5.1.3-5.2.0/2021-08-04--16-00-rename-instance-id.xml::2021-08-04--16-00-rename-instance-id-index.xml::psmahin was: 8:836da301debccfd991c718a04b84ad5e but is now: 8:a7514ad06dbcbe7969a047daf17891dd\n",
  "messages" : [ ]
}

Additional info: RMB-895
We can call the /_/tenant/$id API (again) with a wait parameter until "complete" is true, see description above.
Example: /_/tenant/458b6397-c4d2-46b2-a771-ace8a310bcea?wait=30000

A.I.: Added Wiki page to include in Release notes for module upgrades (not to miss the errors).
https://wiki.folio.org/display/FOLIJET/Module+upgrade+via+Tenant+API