Move "add block" button to block context

[adamziel]

Is your feature request related to a problem? Please describe.
I was very confused about how to add a block, I was looking for some kind of "+" button related to blocks but all I could see was a "+" button in the navigation bar here:

Finally I clicked on it and discovered it is the add block button, I hesitated for some time because it seemed to be related to post as a whole since the same bar contains "save" and "preview" buttons.

Describe the solution you'd like

I would move this "+" button inside the editor like this, it would clearly suggest what is it for:

[ZebulanStanphill]

Related: #6834.

See also the recently-merged new(-ish) in-between inserter design of #6818 that will be included in Gutenberg 3.0.

[karmatosed]

There are a few ways to add a block and the top menu is just one. You can have it beside the content:

You can also add in-between blocks:

For now going to close this as there are a few options to add blocks already there.

[ZebulanStanphill]

Notably, the placeholder block (seen in the first screenshot posted by @karmatosed as well as at the bottom of the second one) does not appear after a Paragraph block. To insert after a Paragraph block requires using the inserter button in the top bar or pressing Enter.

Personally, I think that either the placeholder should always be shown at the bottom of a post, or (and this is my preferred option) the sibling inserter should be usable at the bottom of the last block in a post or nested context. See also: #6834.