(build) Externalize apollo components

[Austio]

This PR reduces the size of the library by between 60-65% across esm/min/umd builds

This PR builds on top of #722 and extracts Apollo components into an includable plugin. I don't think that we require people who are not including these components to include in the bundle.

Library	Before	After WithExternals	After Removing Apollo Components
esm	133k	57k	48k
min	52k	26k	21k
umd	142k	61k	51k

# Current Build
drwxrwxr-x  2 talos talos   4096 Jul  5 11:50 .
drwxrwxr-x 16 talos talos   4096 Aug  7 10:26 ..
-rw-rw-r--  1 talos talos 133190 Aug  7 10:27 vue-apollo.esm.js
-rw-rw-r--  1 talos talos  52935 Aug  7 10:26 vue-apollo.min.js
-rw-rw-r--  1 talos talos 142186 Aug  7 10:27 vue-apollo.umd.js

# With externals
drwxrwxr-x  2 talos talos  4096 Jul  5 11:50 .
drwxrwxr-x 16 talos talos  4096 Aug  7 10:26 ..
-rw-rw-r--  1 talos talos 57047 Aug  7 10:28 vue-apollo.esm.js
-rw-rw-r--  1 talos talos 26922 Aug  7 10:28 vue-apollo.min.js
-rw-rw-r--  1 talos talos 61127 Aug  7 10:28 vue-apollo.umd.js

# With removing apollo
drwxrwxr-x  2 talos talos  4096 Jul  5 11:50 .
drwxrwxr-x 16 talos talos  4096 Aug  7 10:26 ..
-rw-rw-r--  1 talos talos 48084 Aug  7 11:03 vue-apollo.esm.js
-rw-rw-r--  1 talos talos 21970 Aug  7 11:03 vue-apollo.min.js
-rw-rw-r--  1 talos talos 51291 Aug  7 11:03 vue-apollo.umd.js

[Akryum]

Hi, I have plan to tackle this issue in vue-apollo 4, albeit a bit differently.

[Austio]

@Akryum awesome, any reason to not do now? Makes a biggish difference in the bundle size.

[Akryum]

I'd rather not have such a change in the rc, the priority being stabilization and release of 3.0.0