Add chart: Proportion of awards with competitive contracting processes over time

[sabahfromlondon]

Chart details:

• [ ] Type: Single Line Chart
• [ ] Title: Proportion of awards with competitive contracting processes over time
• [ ] Description: Identify which times of the year does competition suffer.
• [ ] X-axis → Month and year
• [ ] Y-axis → Proportion of awards

Additonal details:

• Timestamp to use the date of the compiled release.
• Zoom into shorter time periods.

[Camilamila]

Remove procedures without a tender date

[vgeryarbc]

Removed