Removes ep_page_view plugin from the installation instructions in README.md to aid new users installing etherpad-lite.

According to the plugin directory at https://static.etherpad.org/index.html, the plugin is defunct as it is now part of etherpad-lite core and when I tried installing etherpad with the plugin (following the instructions), its installation resulted in an error every time I opened a pad.

* bugfix, lint and refactor all bin scripts

* for squash: throw Error(message) rather than log(message); throw Error()

* for squash: Exit non-0 on unhandled Promise rejection

Many of the recent lint changes have converted normal functions to
async functions, and an error thrown in an async function does not
cause Node.js to exit by default.

* for squash: fix `require()` paths

* for squash: remove erroneous `Object.keys()` call

* for squash: fix missing `continue` statements

* for squash: Fix HTTP method for deleteSession

* for squash: delete erroneous throw

Throw is only for errors, not successful completion.

* for squash: redo migrateDirtyDBtoRealDB.js to fix async bugs

* for squash: fix erroneous use of `for..of`

* for squash: Add line break between statements

* for squash: put closing paren on same line as last arg

* for squash: Move `log()` back up where it was

to minimize the diff to develop

* for squash: indentation fixes

* for squash: typo fix

* for squash: wrap long lines

* for squash: use `util.callbackify` to silence promise/no-callback-in-promise warning

* for squash: use double quotes to improve readability

Co-authored-by: Richard Hansen <rhansen@rhansen.org>

I thought a PR adding capitalized `Database` landed in ueberdb2, but
apparently not.

This reverts commit 611d416d.

This reverts commit 33baaafbdeb4c0f82ec504738f5851f9ab5261a8.

* remove IE and add strict headers

* linting: kids are back, need to stop for today

* linting: farbtastic fix

* lint: more lint fixes

* more lint fixes

* linting: sub 100 errors

* comments where I need help

* ready to be helped :)

* small fixes

* fixes

* linting: all errors resolved

* linting: remove note to self

* fix as per nulli/wezz000li suggestion

* fix as per nulli/wezz000li suggestion

* resolve merge conflicts

* better use if to silence eslint

* Use `for..of` with `Object.keys` instead of `for..in`

* lint: move setSelection to before call

Co-authored-by: webzwo0i <webzwo0i@c3d2.de>
Co-authored-by: Richard Hansen <rhansen@rhansen.org>

`git add -A` will ignore `node_modules/` because it's in `.gitignore`.

Tweak the new `updateDeps()` function and use it to add the
`ep_etherpad-lite` dependency if it is missing.

This will make it possible to reuse the logic for `peerDependencies`.

This makes it possible to check plugins that were installed by
symlinking into `node_modules/` like this:

    git clone git@github.com:ether/etherpad-lite.git
    git clone git@github.com:ether/ep_example.git
    cd etherpad-lite
    npm i ep_example@file:../ep_example
    node ./bin/checkPlugin.js ep_example

Rather than check for modifications and untracked files in one
command, use two commands: one for modifications and one for untracked
files. This makes the error messages easier to understand, and it
allows us to include `git status`-like output in the modifications
error message.