Bug 1772914

Description of problem:

1) In Section 4.2 step 2 is a duplicate, doc has already asked users to enable required repositories in section 2.5 and user has been asked to follow 2.5 as a prerequisite in 4.2

2) In section 4.2 step 7.i , second example has 'journal_size' which is required only in filestore, a note can be added stating that the example is of filestore as the default objectstore is bluestore.

3) Section 4.2 Step 7.i needs to address details of new container registry and container image name for RHCS4.x and also about ceph_docker_registry_auth and ceph_docker_registry_username, ceph_docker_registry_password
Ref BZ 1722787 

4) Section 4.2 Step 7.ii has examples about collocated and non-collocated scenarios, where as support for the same has been removed in RHCS 4.x
Ref - 1639791
Now user don't need to set osd_scenario to any value.

5) Section 4.7, Prerequisite 3 and Warning after step 5 seems to be outdated
ceph-ansible creates nfs user while configuring nfs in both baremetal and containerized scenarios.

6) In many places when we ask users to run site.yml, reference to site-docker.yml has been missed.
Example -Section 4.7 Step 6

7) Document misses steps for iso based installation. Only section 2.5 has references to iso based installation. We need to provide further steps on installing ceph-ansible and configuring all.yml in installation and upgrade scenario.

8) In Section 5.2, we need to add a note saying that step 7 and 8 are not needed if rbd-mirroring was configured using ceph-ansible.

9) In 5.2 section step 9 has some typos which has caused indentation and numbering of steps issues. Can we please correct them ?

10) In section 4.2 step 9, We are not sure why the change has been suggested to bare metal user. In fact retry files are disabled by default for all users.
Ref - https://github.com/ceph/ceph-ansible/blob/8be15a46f54d30c06c22589005a6a74628d9ec9d/ansible.cfg#L25

11) Section 4.3 Note 1 needs be modified saying that SSDs will not be used for data part. both data and journal/block constitutes OSD.

12) Section 4.6 step 5 is wrong, default port for RGW is 8080
Ref https://github.com/ceph/ceph-ansible/blob/8be15a46f54d30c06c22589005a6a74628d9ec9d/roles/ceph-defaults/defaults/main.yml#L395

13) In section 4.6, step 6 and step 8 are conveying same task. One of them can be removed.

14) Chapter 5 2nd IMPORTANT message is outdated if fixes for 1569689 are in 4.x builds. infact this Important message is causing new issue as mentioned in BZ 1722002 .