improve docs on setting up a new dev environment

[pdurbin]

What this PR does / why we need it:

I got a new laptop and ran into various issue setting up a Dataverse dev environment:

• confusion over which distribution of Java to install confusion over how to install Java 8 from Oracle for potential Dataverse developers #7234
• wrong version of Payara (updated in pull request bump to payara-5.2020.2 per @scolapasta, remove JSF patch #7036)
• using pip before running the installer and having lots to read in the README
• specifically, when running the installer, not having an SMTP server When setting up a dev environment, I don't want to be blocked by not having a mail server #7236

One of our strategic goals is "increase contributions from the open-source development community" and I hope this pull request helps.

The summary is:

• Switch from Oracle JDK to OpenJDK.
• Bring version of Payara inline with version in Installation Guide.
• Avoid need to read long installer README and provide shorter instructions inline.
• Suggest a workaround (netcat running on port 25) instead of requiring new developers to install a mail/SMTP server.
• Various cleanup.

Which issue(s) this PR closes:

• Closes issues setting up a dev environment #7241 issues setting up a dev environment
• Closes confusion over how to install Java 8 from Oracle for potential Dataverse developers #7234 confusion over how to install Java 8 from Oracle for potential Dataverse developers
• Closes When setting up a dev environment, I don't want to be blocked by not having a mail server #7236 When setting up a dev environment, I don't want to be blocked by not having a mail server

Special notes for your reviewer:

I left comments in the commits. Here's a dump of them:

commit 91b835e (HEAD -> 7241-dev-env, origin/7241-dev-env)
Author: Philip Durbin philip_durbin@harvard.edu
Date: Fri Aug 28 12:37:09 2020 -0400

put install.py instructions inline, add venv #7241

The README_python.txt is long and a lot to digest. I still link
to this text file for reference but I simplified the instructions
to put all the commands I used inline.

I also introduced venv which is what I think Python developers
should be using in 2020.

commit 45a85ac
Author: Philip Durbin philip_durbin@harvard.edu
Date: Fri Aug 28 12:32:30 2020 -0400

bump version of postgres (within 9.6), clarify docs #7241

We got a question about all the pgAdmin stuff. What it's for, what's
going on. It wasn't clear that we're simply using this tool to check
if the "trust" change worked (which simplifies the installation later).
Perhaps in the future we could switch to a test with `psql` but an
advantage of mentioning pgAdmin early is to let the new developer know
that this tool exists.

commit 95bfbf1
Author: Philip Durbin philip_durbin@harvard.edu
Date: Fri Aug 28 12:27:40 2020 -0400

remove section on Glassfish/Payara startup time #7241

I had added in in pull request #5438 but I'm not sure we need it.
I didn't seem to need it this time.

commit 4fc67ea
Author: Philip Durbin philip_durbin@harvard.edu
Date: Fri Aug 28 12:22:56 2020 -0400

match version of Payara used in Installation Guide #7241

The Installation Guide was updated in pull request #7036 for #7017.

commit 6402322
Author: Philip Durbin philip_durbin@harvard.edu
Date: Fri Aug 28 12:10:59 2020 -0400

simply Netbeans steps for version 12 #7241

commit 791437c
Author: Philip Durbin philip_durbin@harvard.edu
Date: Fri Aug 28 12:07:53 2020 -0400

recommend OpenJDK instead of Oracle JDK #7234 #7241

Suggestions on how to test this:

Have a another developer run through these instructions, on Mac.

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

No.

Is there a release notes update needed for this change?:

No.

Additional documentation:

None.

[coveralls]

Coverage decreased (-0.05%) to 19.482% when pulling a6c359c on 7241-dev-env into 796e612 on develop.

[mheppler]

@pdurbin am I missing something? Don't see any changes that fixes the mail server issue #7236.

[pdurbin]

@mheppler it's this line:

"The installer will try to connect to the SMTP server you tell it to use. If you don't have a mail server handy you can run nc -l 25 in another terminal and choose "localhost" (the default) to get past this check."

[mheppler]

Ah. I missed that. Sorry, @pdurbin. What does running nc -l 25 do?

[pdurbin]

nc -l 25 starts a service that listens on port 25, the port used by mail servers to send mail (SMTP). When the installer checks the mail server you've configured, it simply checks port 25. In short, nc is a way to make the installer happy without having to configure a mail server.

[mheppler]

👍 Looks good. Don't know if more info is needed for the ns-SMTP server work around. I'll leave that up to QA.