standard_app: allow URL to be defined in app makefile

[sgliner-ledger]

Description

Allow app to define only the URL in its makefile

Changes include

• Bugfix (non-breaking change that solves an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)
• Tests
• Documentation
• Other (for changes that might not fit in any category)

[codecov-commenter]

Codecov Report

Patch and project coverage have no change.

Comparison is base (beb209d) 69.09% compared to head (b570644) 69.09%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #388   +/-   ##
=======================================
  Coverage   69.09%   69.09%           
=======================================
  Files          11       11           
  Lines         864      864           
=======================================
  Hits          597      597           
  Misses        267      267           

Flag	Coverage Δ
unittests	69.09% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.