Update F20,F1 & F1bis from the 4/2015 adding new constrains

[AdriNicolau]

Description:

• Added the constrain that requires the CUPS to have a modcon in the current year.
• Excluded the CUPS with tarifas like 'RE'

Tasks:

• [x] Documented the modcon constrain
• [x] Documented the exclusion of the 'RE'

Links:

docs/distri/adm-pub/resoluciones/circular_4-2015.md

• 4/2015 #F1 ES
• 4/2015 #F1bis ES
• 4/2015 #F20 ES
• 4/2015 #F1 CAT
• 4/2015 #F1bis CAT
• 4/2015 #F20 CAT

[giscegit]

Documentation build URL: http://builds.gisce.net/powerp-docs/powerp_update_F20_F1_F1bis_from_4_2015_doc/

Things to review:

• [ ] Typos in Catalan
• [ ] Typos in Spanish
• [ ] Links routes in Spanish
• [ ] Links work in Catalan
• [ ] Links work in Spanish
• [ ] Images in Spanish
• [ ] Page index shows all headers

[giscegit]

Documentation build URL: http://builds.gisce.net/powerp-docs/powerp_update_F20_F1_F1bis_from_4_2015_doc/

Things to review:

• [ ] Typos in Catalan
• [ ] Typos in Spanish
• [ ] Links routes in Spanish
• [ ] Links work in Catalan
• [ ] Links work in Spanish
• [ ] Images in Spanish
• [ ] Page index shows all headers