Add searchbar

[ByteOtter]

What does this PR change?

Allows users to search for users and posts and filter by using a user:<username>, topic:<topic> and/or image:true flags.

current problems (check if fixed):

• [ ] HTML Form input field does not enter route on submit
• [ ] input field value is empty on submit
• [ ] search function not implemented correctly

Tick the applicable box:

• [x] Add new feature

• [ ] UI improvement

• [ ] Changed routing

• [ ] Security changes

• [ ] Testsuite
  

• [ ] General Maintenance

UI changes

provide description here or remove all unapplicable lines below

• Internal / User invisilbe changes only
• No changes

before: nA

after: searchbar added add the top

• [x] DONE

Links

In case your changes fix an existing issue please link it below:

Fixes: #95

• [x] DONE

Documentation

provide description about documentation done here or remove this line

• No documentation needed
  

• [x] DONE