chore: consistent script names for travis setup (#5986)

* Updates the outdated README in the `ci/` folder.
* Renames the `env.sh` script to `travis-env.sh` because it only works for Travis and is not a generic script.

.travis.yml

@@ -42,7 +42,7 @@ env:
   - BROWSER_PROVIDER_ERROR_FILE=/tmp/angular-material2-build/errorfile
 
 before_install:
-  - source ./scripts/ci/env.sh
+  - source ./scripts/ci/travis-env.sh
   - npm i -g npm@^5.3.0
 
 install:

scripts/ci/README.md

@@ -2,6 +2,9 @@
 
 This directory contains scripts that are related to CI only.
 
-### `build-and-test.sh`
-
-The main script. Setup the tests environment, build the files using the `angular-cli` tool and run the tests.
+| Script            | Description                                                           |
+| ----------------- | --------------------------------------------------------------------- |
+| travis-env.sh     | Runs at the beginning of a Travis build to set up the environment.    |
+| travis-script.sh  | Main script that Travis will always execute for every job and mode.   |
+| travis-testing.sh | Script that controls all jobs inside of the testing build stage.      |
+| travis-deploy.sh  | Script that controls all jobs inside of the deploy build stage.       |