Rework when the "save" tab is shown, and when the file being edited is considered a template.

Basically, any file that is not in the course's templates directory is
now considered a template, and for these files the "save" tab is not
shown.  Note that this uses the `WeBWorK::Utils::Files::path_is_subdir`
method, and so files that are linked to from the course's templates
directory are not considered templates. Although, if those files are not
writable by the server, then the message `The file "[_1]" is protected.
You may use "Save As" to create a new file.` will be shown. So OPL or
Contrib problems will not be considered templates, but if file
permissions are correct on your server, then the message above will be
shown.  However, if a file is in a location in `$webworkDirs{valid_symlinks}`
array, and file permissions are correct on your server, then no message
will be shown, and the file can be saved.

Author: drgrice1

lib/WeBWorK/ContentGenerator/Instructor/PGProblemEditor.pm

@@ -129,8 +129,6 @@ use constant ACTION_FORM_TITLES => {
 	revert           => x('Revert'),
 };
 
-my $BLANKPROBLEM = 'newProblem.pg';
-
 sub pre_header_initialize ($c) {
 	my $ce    = $c->ce;
 	my $authz = $c->authz;
@@ -247,14 +245,11 @@ sub initialize ($c) {
 		));
 	}
 
-	if ($c->{file_type} eq 'blank_problem' || $c->{file_type} eq 'sample_problem') {
-		$c->addbadmessage($c->maketext('This file is a template. You may use "Save As" to create a new file.'));
-	} elsif ($c->{inputFilePath} =~ /$BLANKPROBLEM$/) {
-		$c->addbadmessage($c->maketext(
-			'The file "[_1]" is a template. You may use "Save As" to create a new file.',
-			$c->shortPath($c->{inputFilePath})
-		));
-	}
+	$c->addbadmessage($c->maketext(
+		'The file "[_1]" is a template. You may use "Save As" to create a new file.',
+		$c->shortPath($c->{inputFilePath})
+	))
+		if !path_is_subdir($c->{editFilePath}, $ce->{courseDirs}{templates});
 
 	# Find the text for the editor, either in the temporary file if it exists, in the original file in the template
 	# directory, or in the problem contents gathered in the initialization phase.

templates/ContentGenerator/Instructor/PGProblemEditor/save_form.html.ep

@@ -1,8 +1,6 @@
-% # Can't save blank problems without changing names, and can't save if lacking write permissions.
-% last if $c->{file_type} eq 'blank_problem'
-	% || $c->{file_type} eq 'sample_problem'
-	% || $c->{editFilePath} =~ /newProblem\.pg$/
-	% || !-w $c->{editFilePath};
+% use WeBWorK::Utils::Files qw(path_is_subdir);
+% # Can't save files outside of the course templates directory, and can't save if lacking write permissions.
+% last if !path_is_subdir($c->{editFilePath}, $ce->{courseDirs}{templates}, 1) || !-w $c->{editFilePath};
 %
 <div>
 	<div class="mb-2">