Docs: Update references to XUL for web client

[Remington Steed]

The official documentation has several textual references to the XUL client or related files. This bug is meant to find and update them. Here's an initial attempt to find them:

The list below was produced by this grep command:

grep -lri xul *

----------------
admin/staff_client-column_picker.adoc
admin/staff_client-login.adoc
admin/audio_alerts.adoc
cataloging/marc_tag_table.adoc
circulation/basic_holds.adoc
circulation/advanced_holds.adoc
installation/server_upgrade.adoc
installation/server_installation.adoc
installation/staff_client_installation.adoc
root.adoc

[Andrea Neiman (aneiman)]

Went through these over the past couple of days and here's how they stand now. I will be attaching PR's for a few of the smaller items. Corrections to filepaths, symlink instructions, etc. are outside my current skillset.

admin/staff_client-column_picker.adoc -- master reflects webclient info

admin/staff_client-login.adoc -- master reflects webclient info

admin/audio_alerts.adoc -- still contains references to XUL in the filepath for defining sounds in the audio_config.tt2 template

cataloging/marc_tag_table.adoc -- MARC tag-table is Angularized & part of Server Admin in the web client; however, tooltips are not currently working in web client (bug 1746025) -- not sure what DIG wants to do about that fact. Small PR forthcoming to strike the "sprint 2 preview" language.

circulation/basic_holds.adoc -- noting that patron search will not appear in the XUL client. Small PR forthcoming to strike this language.

circulation/advanced_holds.adoc -- all of this is updated for the web client, except the section Display Hold Types on Pull Lists -- that whole section to be rewritten & re-screenshot. I will take a crack at that next week if I have time.

installation/server_upgrade.adoc -- XUL reference in the instructions for updating server symlink

installation/server_installation.adoc -- XUL reference in the instructions for creating server symlink

installation/staff_client_installation.adoc -- this whole section can probably be removed for the 3.2 docs

root.adoc -- reference is "For information about the XUL client, consult the Evergreen 2.11 documentation." Small PR forthcoming to strike this sentence.

[Andrea Neiman (aneiman)]

cataloging/marc_tag_table.adoc -- PR here, also includes location info & screenshots: https://github.com/evergreen-library-system/Evergreen/pull/57

circulation/basic_holds.adoc -- PR here: https://github.com/evergreen-library-system/Evergreen/pull/58

root.adoc -- PR here: https://github.com/evergreen-library-system/Evergreen/pull/59

[Remington Steed (rjs7)]

Thanks for looking into these, Andrea. Two quick comments:

- Install/upgrade instructions will hopefully be changed when the XUL code is actually removed.

- root.adoc: This comment was meant for those who haven't switched to the web client yet, since the 2.11 docs are the most recent XUL docs that we have. I think we'll want to keep this comment, at least until the XUL client is entirely unsupported (i.e. when 3.1 is no longer supported).

[Andrea Neiman (aneiman)]

Thanks for the feedback -- I removed the PR for root.adoc