This commit gets rid of all references to Travis and, belatedly, Jenkins.
Now all CI is done on CircleCI and releases are run locally.

The CI no longer updates the docs and code.angularjs.org for jobs that are
not on the `master` branch.

During releases, the docs and code should be uploaded manually.

By blocking `__proto__` on deep merging, this commit
prevents the `Object` prototype from being polluted.

Previously the test was assuing that this function was attached to
the window, which is not the case in production, nor in the isolated
module tests.

SauceLabs  is struggling to keep connecting and disconnecting
for each of the modules unit test runs. This commit puts most of
the module tests into IIFEs so that they can be run in one go.

* ngMock is still tested separately since unlike the other tests
it doesn't want to have a pre-built version of ngMock available.

* ngAnimate is still tested separately because it does some funny
things with globals that were difficult to isolate in the main modules
test run.

…ributes

By creating attribute directives that watch the value of
media url attributes (e.g. `img[src]`) we caused a conflict
when both `src` and `data-src` were appearing on the
same element. As each directive was trying to write to the
attributes on the element, where AngularJS treats `src` and
`data-src` as synonymous.

This commit ensures that we do not create create such directives
when the media url attribute is a constant (no interpolation).

Because of this (and because we no longer sanitize URLs in the
`$attr.$set()` method, this commit also updates `ngHref` and
`ngSrc` to do a preliminary sanitization of URLs in case there
is no interpolation in the attribute value.

Fixes #16734

Without the path the link is always pointing to the
root page, rather than the current page, which means
that copying the link address or opening the page in
a new tab is broken.

Closes #16608