Improve landing page

[northwestwitch]

This PR adds | fixes:

• Clicking on number of datasets on landing page opens a modal with the description of each dataset (fix Expand description of datasets on landing page #200)
• Add tooltips explaining that coords are 0 based (in HTML query form)
• According to the official APIs, / endpoint should return json info data. Changed accordingly

How to prepare for test:

• Install on cg-v1 and check that the above things work as intended

Review:

• Code approved by
• Tests executed by CR
• "Merge and deploy" approved by

This version is a:

• MAJOR - when you make incompatible API changes
• MINOR - when you add functionality in a backwards compatible manner
• PATCH - when you make backwards compatible bug fixes or documentation/instructions

[codecov]

Codecov Report

Merging #204 (a441673) into main (75a88ee) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #204   +/-   ##
=======================================
  Coverage   95.46%   95.47%           
=======================================
  Files          57       57           
  Lines        2582     2583    +1     
=======================================
+ Hits         2465     2466    +1     
  Misses        117      117           

Flag	Coverage Δ
unittests	95.47% <100.00%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
cgbeacon2/server/blueprints/api_v1/controllers.py	97.33% <ø> (ø)
cgbeacon2/server/blueprints/api_v1/views.py	99.18% <100.00%> (+<0.01%)	⬆️

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[northwestwitch]

• Check that / endpount returns json info: 🆗

• Check that 0-based coords tooltips work: 🆗

• Check that dataset info modal works: 🆗