[PATCH] Let's rework the Quick Start page (publish/quick-start.html)

Hello,

It appears that the current SVN Quick Start page[1] is kind of desolate; there
is a discussion about updating it[2]. I want to volunteer for this task and I am
attaching a patch. :)

My idea is to provide novice SVN end users with a quick reference on the most
basic concepts and operations:
* checkout a working copy,
* update the working copy,
* modify the data in the working copy and commit it,
* make a branch or tag.

A user who needs help on how to begin working with SVN does not have to dive
into the SVNBook. Yes, he will read the SVNBook some time later to learn more
about basic operations and to find out about the magic of the complex ones. But
not on his first day when the only commands he needs are `svn checkout` and
`svn commit`.

Log Message:
[[[
  * publish/quick-start.html:
    Reworking the SVN Quick Start page as discussed in
    https://lists.apache.org/thread.html/da5b9f351a1bf2456aeb85e24ed88ff30b544a70995638af684684f1@%3Cdev.subversion.apache.org%3E
]]]

[1]: https://subversion.apache.org/quick-start
[2]: https://lists.apache.org/thread.html/da5b9f351a1bf2456aeb85e24ed88ff30b544a70995638af684684f1@%3Cdev.subversion.apache.org%3E