Add underscore replacement string and excluded templates

[kmac23va]

Made the following changes:

• Updated Sitecore version to 9.3
• Added an underscore replacement string for type name. If keepLeadingUnderscores is false and userscoreReplaceString has a value, it's used for type names. For example, if userscoreReplaceString is "Meta" then _Template becomes IMetaTemplate.
• Added an excluded template node. If used, that template will not be generated at all.

[blipson89]

Closed by mistake