Fixes for tinymce modal editor bookmarklet

[lauri457]

PR Description:

Fixed bugs in bookmarklet script

• Updated tinymce dependency to load with native ScriptLoader api
• Properly remove editor when modal closes so that editor can be opened again without refreshing on same page using bookmarklet
• Fixed not working on page without top navigation. Editor can now be opened on any ui page without fatal error
• Minor visual updates
• Fixed issues with z-axis positioning of bookmarklet modal and tinymces plugin modals

Updated readme and screenshot
Added more plugins in toolbar by expanding the init config e.g. accordion, code block, word/char counter

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[am-shakeel]

Looks good