[RUMF-621] set view referrer to the previous view URL

[BenoitZugmeyer]

Motivation

For route_change views, use the previous view URL as referrer.

Changes

For the sake of simplicity, lifecycle types have been improved a bit so we can re-use them easily. Then, the referrer has been set to the View context so it can be used everywher the View context is used. Finally, the view collections is retrieving the previous view URL when creating the new view on URL change or session renew.

Testing

---

I have gone over the contributing documentation.

[mquentin]

with Small NIT

[codecov-commenter]

Codecov Report

Merging #507 into master will increase coverage by 0.33%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #507      +/-   ##
==========================================
+ Coverage   87.61%   87.94%   +0.33%     
==========================================
  Files          35       35              
  Lines        2156     2157       +1     
  Branches      434      434              
==========================================
+ Hits         1889     1897       +8     
+ Misses        267      260       -7     

Impacted Files	Coverage Δ
packages/rum/src/lifeCycle.ts	100.00% <ø> (ø)
packages/rum/src/parentContexts.ts	98.24% <ø> (ø)
packages/rum/src/rum.entry.ts	73.21% <ø> (ø)
packages/rum/src/userActionCollection.ts	98.00% <ø> (ø)
packages/rum/src/rum.ts	91.47% <100.00%> (+4.65%)	⬆️
packages/rum/src/viewCollection.ts	96.29% <100.00%> (+0.03%)	⬆️
packages/rum/src/performanceCollection.ts	63.33% <0.00%> (+1.66%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3e11e98...691c0c9. Read the comment docs.

[bcaudan]

Nice job!