docs: update `README`

[aljo242]

Update the README file:

• remove most of the ignite boilerplate
• add badges
• update URLs

We should make an issue for further updating this file, as this is just a good starting point. If we like this, we could add similar badges to the ignite CLI repo

[codecov[bot]]

Codecov Report

Merging #902 (fbe3221) into develop (1858505) will decrease coverage by 0.00%. The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #902      +/-   ##
===========================================
- Coverage    10.42%   10.42%   -0.01%     
===========================================
  Files          330      330              
  Lines        76837    76837              
===========================================
- Hits          8013     8011       -2     
- Misses       68634    68635       +1     
- Partials       190      191       +1     

Impacted Files	Coverage Δ
x/campaign/simulation/store.go	81.08% <0.00%> (-1.36%)	:arrow_down: