Miscellaneous clean-up for upcoming changes

- Remove BOM from new files.
- Remove redundant xml tags and attributes.
- Update Git ignores and attributes.
- Ensure to preserve encoding of `UTF-16LE` files.
- Update Toolkit Icons and use `Icon.png` name instead.
- Rename solution, scripts and NuGet config files.
- Remove leftover files from previous refactors.
- Format Notifications package ReadMe.
- Remove redundant code from project files.
- Update Comments and fix mistakes.

Author: Nirmal4G

.editorconfig

@@ -41,6 +41,10 @@ indent_size = 2
 indent_size = 2
 insert_final_newline = true
 
+# Special files
+[*.UTF-16LE.*]
+charset = utf-16le
+
 # C# files
 [*.cs]
 

.gitattributes

@@ -1,63 +1,53 @@
-###############################################################################
-# Set default behavior to automatically normalize line endings.
-###############################################################################
+# Set default file-type attributes
+
+# All file types
 * text=auto
 
-###############################################################################
-# Set default behavior for command prompt diff.
-#
-# This is need for earlier builds of msysgit that does not have it on by
-# default for csharp files.
-# Note: This is only used by command line
-###############################################################################
-#*.cs     diff=csharp
-
-###############################################################################
-# Set the merge driver for project and solution files
-#
-# Merging from the command prompt will add diff markers to the files if there
-# are conflicts (Merging from VS is not affected by the settings below, in VS
-# the diff markers are never inserted). Diff markers may cause the following
-# file extensions to fail to load in VS. An alternative would be to treat
-# these files as binary and thus will always conflict and require user
-# intervention with every merge. To do so, just uncomment the entries below
-###############################################################################
-#*.sln       merge=binary
-#*.csproj    merge=binary
-#*.vbproj    merge=binary
-#*.vcxproj   merge=binary
-#*.vcproj    merge=binary
-#*.dbproj    merge=binary
-#*.fsproj    merge=binary
-#*.lsproj    merge=binary
-#*.wixproj   merge=binary
-#*.modelproj merge=binary
-#*.sqlproj   merge=binary
-#*.wwaproj   merge=binary
-
-###############################################################################
-# behavior for image files
-#
-# image files are treated as binary by default.
-###############################################################################
-#*.jpg   binary
-#*.png   binary
-#*.gif   binary
-
-###############################################################################
-# diff behavior for common document formats
-#
-# Convert binary document formats to text before diffing them. This feature
-# is only available from the command line. Turn it on by uncommenting the
-# entries below.
-###############################################################################
-#*.doc   diff=astextplain
-#*.DOC   diff=astextplain
-#*.docx  diff=astextplain
-#*.DOCX  diff=astextplain
-#*.dot   diff=astextplain
-#*.DOT   diff=astextplain
-#*.pdf   diff=astextplain
-#*.PDF   diff=astextplain
-#*.rtf   diff=astextplain
-#*.RTF   diff=astextplain
+# Markups
+*.md   text=auto diff=markdown
+*.mdx  text=auto diff=markdown
+
+# Solutions
+*.sln   text=auto eol=crlf
+*.slnx  text=auto
+
+# Projects
+*.*proj    text=auto
+*.tasks    text=auto
+*.props    text=auto
+*.targets  text=auto
+
+# Sources
+*.cs    text=auto diff=csharp
+*.csx   text=auto diff=csharp
+*.resx  text=auto
+
+# Scripts
+*.in   text eol=lf
+*.sh   text eol=lf
+*.bat  text eol=crlf
+*.cmd  text eol=crlf
+
+# Images
+*.png  binary
+*.jpg  binary
+*.gif  binary
+
+# Keys
+*.snk  binary
+*.pfx  binary
+*.cer  binary
+
+# Others
+
+# Preserve Line endings in diff and patch files
+*.diff   -text
+*.patch  -text
+
+# Exclude git meta files from exporting
+.gitattributes export-ignore
+.gitignore     export-ignore
+.gitkeep       export-ignore
+
+# Ours
+*.UTF-16LE.* encoding=utf-16le