Docs: Change all docs filenames to end with .adoc

[Remington Steed]

At the 2017 conference, several people revived the idea of using the AsciiDoc filename extension ".adoc" for all of our docs files, especially since GitHub provides an HTML preview of these files. Here is a working branch that makes the change. Note: The diff is ugly because every filename is changed. However, the only file that has changed is root.adoc (formerly root.txt), where all the filename references have changed to ".adoc" as well.

http://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/rsteed/docs_rename_files_to_adoc

History: The community agreed to this change in 2015 (see http://markmail.org/thread/z2s7xnxavpjzirwx).

NOTE: Whenever this is pushed into the main repository, we also need to update the docs build script to point to "root.adoc" instead of "root.txt".

[Bill Erickson (berick)]

Here's a patch to repair the README/INSTALL symlinks in the base of the repository. The previously linked to server_installation.txt, which created the following errors trying to build Evergreen:

Makefile.am: error: required file './README' not found
autoreconf: automake failed with exit status: 1

http://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/berick/lp1682447-readme-adoc-symlink

[Bill Erickson (berick)]

Above patch needs sign-off and back-porting to master/2.12/2.11

[Jeff Godin (jgodin)]

Signed off and pushed Bill's fix to master, rel_2_12, rel_2_11.

Remington, over to you -- I'm not sure if the task mentioned in the bug's original description is still outstanding:

> NOTE: Whenever this is pushed into the main repository, we also need to update the docs build script to point to "root.adoc" instead of "root.txt".

[Remington Steed (rjs7)]

Thanks Bill and Jeff for the fix.

And yes, the docs build script has been updated (thanks to Robert Soulliere). I'll mark this bug as committed.