Screenshots were recently updated for 4.2.beta's revamped project
manager UI.
This also changes GUI option formatting to use bold text as is
standard elsewhere in the documentation.
There were a few places in docs that still referenced "Templates Tabs"
and needed updated to the new name "Asset Library Projects Tab".
I also converted any images I touched from png to webp and compressed
them using sqoosh.app.
Extracted and edited the project manager from
intro_to_the_editor_interface.rst, added it in the tutorials/editor
section
Wrote a short introduction for the editor section
