[BUG] Fix Various Ckeditor Bugs

Desktop (please complete the following information):

Development

[x] fix images uploaded from user machine not displaying
- why are these being stripped out?
- iframe sanitization hook was catching all things being sanitized that werent iframes too
[x] fix image captioning not being centered below image
- had to apply manual css to clear the background
- since editor bg manually cleared too
[x] fix image alignment not being applied
- only happens w/ not LHS justified and not surrounded by text
- fixed thru using "ck-content" classname alongside singlePostDescription
- wherever ckeditor implimented
- in single post page only for now
[x] rm white and light-grey as text color options
- almost, if not impossible to see this color on light bg
- had to re-add all the other colors as manually
- so left some seemingly extra ones out
- used the color dropper to get their colors from the default color palette
[x] fix red and green highlighters
- they only color the text, not the bg of the text
- that's bc they're pens, not markers
- so i'll rm them since have text color changing dropdown
[x] fix some paragraph text not being previewed
- may only happen to paragraph text with styling on it
- yes bc that styling adds more html tags that aren't allowed thru the filter
- ended up adding alot more tags thru the filter thru manual addition of them
- or paragraph text after iframe or img
[x] fix can't increase or decrease the indent
- can occasionally use these btns but not intuitive when u can use them

SethCram / book-club