.pytool/Plugin: Add CI plugins

https://bugzilla.tianocore.org/show_bug.cgi?id=2315

Add .pytool directory to the edk2 repository with the
following plugins.  These plugins are in a top level
directory because that can be used with all packages
and platforms.

* CharEncodingCheck
* CompilerPlugin
* DependencyCheck
* DscCompleteCheck
* GuidCheck
* LibraryClassCheck
* SpellCheck

Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

.pytool/Plugin/SpellCheck/Readme.md

@@ -0,0 +1,127 @@
+# Spell Check Plugin
+
+This CiBuildPlugin scans all the files in a given package and checks for
+spelling errors.
+
+This plugin requires NodeJs and cspell.  If the plugin doesn't find its required
+tools then it will mark the test as skipped.
+
+* NodeJS: https://nodejs.org/en/
+* cspell: https://www.npmjs.com/package/cspell
+  * Src and doc available: https://github.com/streetsidesoftware/cspell
+
+## Configuration
+
+The plugin has a few configuration options to support the UEFI codebase.
+
+``` yaml
+  "SpellCheck": {
+      "AuditOnly": False,          # If True, log all errors and then mark as skipped
+      "IgnoreFiles": [],           # use gitignore syntax to ignore errors in matching files
+      "ExtendWords": [],           # words to extend to the dictionary for this package
+      "IgnoreStandardPaths": [],   # Standard Plugin defined paths that should be ignore
+      "AdditionalIncludePaths": [] # Additional paths to spell check (wildcards supported)
+  }
+```
+
+### AuditOnly
+
+Boolean - Default is False.
+If True run the test in an Audit only mode which will log all errors but instead
+of failing the build it will set the test as skipped.  This allows visibility
+into the failures without breaking the build.
+
+### IgnoreFiles
+
+This supports .gitignore file and folder matching strings including wildcards
+
+* All files will be parsed regardless but then any spelling errors found within
+  ignored files will not be reported as an error.
+* Errors in ignored files will still be output to the test results as
+  informational comments.
+
+### ExtendWords
+
+This list allows words to be added to the dictionary for the spell checker when
+this package is tested.  These follow the rules of the cspell config words field.
+
+### IgnoreStandardPaths
+
+This plugin by default will check the below standard paths.  If the package
+would like to ignore any of them list that here.
+
+```python
+[
+# C source
+"*.c",
+"*.h",
+
+# Assembly files
+"*.nasm",
+"*.asm",
+"*.masm",
+"*.s",
+
+# ACPI source language
+"*.asl",
+
+# Edk2 build files
+"*.dsc", "*.dec", "*.fdf", "*.inf",
+
+# Documentation files
+"*.md", "*.txt"
+]
+```
+
+### AdditionalIncludePaths
+
+If the package would to add additional path patterns to be included in
+spellchecking they can be defined here.
+
+## Other configuration
+
+In the cspell.base.json there are numerous other settings configured.  There is
+no support to override these on a per package basis but future features could
+make this available.  One interesting configuration option is `minWordLength`.
+Currently it is set to _5_ which means all 2,3, and 4 letter words will be
+ignored.  This helps minimize the number of technical acronyms, register names,
+and other UEFI specific values that must be ignored.
+
+## False positives
+
+The cspell dictionary is not perfect and there are cases where technical words
+or acronyms are not found in the dictionary.  There are three ways to resolve
+false positives and the choice for which method should be based on how broadly
+the word should be accepted.
+
+### CSpell Base Config file
+
+If the change should apply to all UEFI code and documentation then it should be
+added to the base config file `words` section.  The base config file is adjacent
+to this file and titled `cspell.base.json`.  This is a list of accepted words
+for all spell checking operations on all packages.
+
+### Package Config
+
+In the package `*.ci.yaml` file there is a `SpellCheck` config section.  This
+section allows files to be ignored as well as words that should be considered
+valid for all files within this package.  Add the desired words to the
+"ExtendedWords" member.
+
+### In-line File
+
+CSpell supports numerous methods to annotate your files to ignore words,
+sections, etc.  This can be found in CSpell documentation.  Suggestion here is
+to use a c-style comment at the top of the file to add words that should be
+ignored just for this file.  Obviously this has the highest maintenance cost so
+it should only be used for file unique words.
+
+``` c
+// spell-checker:ignore unenroll, word2, word3
+```
+
+or
+
+```ini
+# spell-checker:ignore unenroll, word2, word3
+```