Support for builder specific templates

[alanhartless]

Q	A
Branch?	"features"
Bug fix?	no
New feature?	yes
Deprecations?	no
BC breaks?	no
Automated tests included?	yes
Related user documentation PR URL	n/a
Related developer documentation PR URL	mautic/developer-documentation#185

Description:

This enables plugins to identify itself as providing a "builder" integration. Mautic will then filter themes based on the builder that is enabled (will only acknowledge the first one it finds if there happens to be multiple for a given feature).

Companion PR for the GrapeJS plugin is here mautic/plugin-grapesjs-builder#42.

Steps to test this PR:

1. Load up this PR (must be done locally because GrapeJS has to be installed during the steps)
2. You should see all legacy themes when creating an email or landing page
3. Install the GrapeJS plugin with Registers the plugin as a "builder" plugin-grapesjs-builder#42 patched into it
4. Leave the plugin disabled and create a new email. All Legacy themes should be displayed.
5. Enable the GrapeJS plugin in /s/plugins
6. Create a new email and note that no themes are displayed (because no themes are available yet)
7. Go to the config.json file of the "blank" theme and add "builder": "grapesjsbuilder" to the json object
8. Create an email again and note that the blank theme now shows up (and no others)
9. Go to /s/themes and you should see Legacy badge for all themes except Blank which will show will GrapesJS.

[codecov]

Codecov Report

Merging #9654 (870652f) into features (cd7e257) will increase coverage by 0.01%.
The diff coverage is 84.41%.

@@              Coverage Diff               @@
##             features    #9654      +/-   ##
==============================================
+ Coverage       38.33%   38.35%   +0.01%     
- Complexity      33939    33957      +18     
==============================================
  Files            1982     1984       +2     
  Lines          104948   104997      +49     
==============================================
+ Hits            40236    40274      +38     
- Misses          64712    64723      +11     

Impacted Files	Coverage Δ	Complexity Δ
.../bundles/CoreBundle/Controller/ThemeController.php	0.00% <0.00%> (ø)	29.00 <0.00> (ø)
...rationsBundle/Helper/BuilderIntegrationsHelper.php	68.18% <68.18%> (ø)	11.00 <11.00> (?)
...dencyInjection/Compiler/BuilderIntegrationPass.php	80.00% <80.00%> (ø)	2.00 <2.00> (?)
app/bundles/CoreBundle/Helper/ThemeHelper.php	62.10% <95.74%> (+3.10%)	83.00 <11.00> (+5.00)
.../bundles/IntegrationsBundle/IntegrationsBundle.php	100.00% <100.00%> (ø)	1.00 <0.00> (ø)

[kuzmany]

Works as describe.
Good job

found that it looks like when you edit an existing resource, you can make changes and save them, however the wrong template will show in the dropdown because the one that was used originally is not available (assuming they did not add the line in the config file for the template). We need to document this if that is the case and make sure that people are aware, before they start working with the builder.

This is weird, but I think older templates are editable in grapejs in good way.
Still this is better like previous state, and we can improve it later...