Widgets Improvements

[offtherailz]

Description

Improve current widgets system with some new features.

Please indicate if this issue is related to a bug or a new feature request

• [ ] Bug
• [x] New Feature

Acceptance Criteria - AC

• [x] requires #2642. Possibility to display simple number indicator (without a chart) for max, min, average, sum, stddev.
• [x] requires #2659. Improve widgets layout on map
• [x] requires #2650. Improve legend presentation for pie chart.
• [ ] requires #2653. Query form messages should be customized for the current usage (now it shows search, Advanced Search ... but it should be have "Configure the filter" as title and "Save" instead of "Search" for the primary action button.
• [x] requires #2667. Allow full screen.
• [x] requires #2652. Rethink gauge chart (TODO specify) and colors (for better reading)
• [x] requires #2623. Tabular view of data (with virtual scrolling)
• [ ] requires #2654. Advanced chart options (feedback from C040):
• [x] requires #2655. Minor changes to widgets and charts to evaluate (feedback from C040):
• [x] requires #2651. indicate percentage on pie charts
• [ ] GEOT-5844 - GEOT-5890 Null values in aggregate process rises an exception on GeoServer
• [x] requires #2656. Improve available colors and color ranges.
• [ ] requires #2657. Multivariable charts.
• [x] requires #2658. Export legend in image.
• [ ] requires #2684. Make Group By and Operation optionals
• [x] requires #2675 --> Remove Gauge widget for the time being
• [ ] requires #2676 --> Implement STD for the Counter Widget
• [ ] requires #2677 --> Improve Text Alignment for Counter
• [ ] requires #2678 --> Improve Text Widget L&F
• [ ] requires #2681 --> Label Change in Pie Chart
• [ ] requires #2687 -->Counter Widget should have configurable text options
• [ ] requires #2680 -->ColorRamp not selected when editing existing chart
• [x] requires #2682 -->Allow people to start building a chart from the FeatureGrid
• [ ] requires #2690
• [ ] requires #2684 -->Make # of rows configurable -->Make # of rows configurable
• [ ] requires #2684 -->Introduce possibility to view data and potentially query
• [ ] requires #2691 -->Introduce ordering on column for table widget