feat(txt-registry): deprecate legacy txt-format

[ivankatliarchuk]

trafficstars

Description

• follow-up for https://github.com/kubernetes-sigs/external-dns/pull/4946
• relates https://github.com/kubernetes-sigs/external-dns/pull/4624
• relates https://github.com/kubernetes-sigs/external-dns/issues/3757

TODO:

• ✅ fix tests
• ✅ test on real cluster and account
• ✅ review docs
• ✅ added TXT legacy record cleanup script

Checklist

• [X] Unit tests updated
• [X] End user documentation updated

Executed on real cluster with arguments

go run main.go \
    --provider=aws \
    --registry=txt \
    --source=fake \
    --aws-zone-type=private \
    --zone-id-filter=/hostedzone/XXXXXX \
    --log-level=debug \
    --policy=sync \
    --interval=60s \
    --fqdn-template=a1.ex.com

Without change, records current and old format created

aws route53 list-resource-record-sets --hosted-zone-id ${ZONE_UNDER_TEST} --query "ResourceRecordSets[?Type=='TXT'].{Name:Name, Value:ResourceRecords[0].Value}" --output table
-----------------------------------------------------------------------------
|                          ListResourceRecordSets                           |
+--------------------+------------------------------------------------------+
|        Name        |                        Value                         |
+--------------------+------------------------------------------------------+
|  a-fhbr.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-gwbl.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-hgmc.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-hmqw.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-hoxg.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-ipfd.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-melr.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-mkde.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-uknh.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-xiqj.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  fhbr.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  gwbl.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  hgmc.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  hmqw.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  hoxg.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  ipfd.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  melr.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  mkde.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  uknh.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  xiqj.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
+--------------------+------------------------------------------------------+

With the change. New format records created, letagcy TXT records left untouched

❯❯ aws route53 list-resource-record-sets --hosted-zone-id ${ZONE_UNDER_TEST} --query "ResourceRecordSets[?Type=='TXT'].{Name:Name, Value:ResourceRecords[0].Value}" --output table
-----------------------------------------------------------------------------
|                          ListResourceRecordSets                           |
+--------------------+------------------------------------------------------+
|        Name        |                        Value                         |
+--------------------+------------------------------------------------------+
|  a-dkmw.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-ihkf.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-iztb.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-jlmh.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-kmam.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-lqpv.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-rizx.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-sjfa.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-uvlq.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  a-vgpc.a1.ex.com. |  "heritage=external-dns,external-dns/owner=default"  |
|  bwwo.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  ecvx.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  ilan.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  iyda.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  nhhy.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  pazy.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  sdeo.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  tosb.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  wrej.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
|  yymt.a1.ex.com.   |  "heritage=external-dns,external-dns/owner=default"  |
+--------------------+------------------------------------------------------+
``