Separate Tornado handlers into their own class

[davidbrochart]

References

This will make it easier to support Jupyverse (see #984).

Code changes

This PR moves the Tornado-specific parts (the GET handlers) into their own class.

User-facing changes

None.

Backwards-incompatible changes

None.

[github-actions]

👈 Launch a Binder on branch davidbrochart/voila/get

[davidbrochart]

CI failures are unrelated, see #1331.

[trungleduc]

Hey @davidbrochart, could you rebase your PR, the CI is fixed.

[github-actions]

Benchmark report

The execution time (in milliseconds) are grouped by test file, test type and browser.
For each case, the following values are computed: min <- [1st quartile - median - 3rd quartile] -> max.

Results table

Test file	voila-tree-classic.ipynb	voila-tree-light.ipynb	voila-tree-dark.ipynb	voila-tree-miami.ipynb	basics.ipynb	bqplot.ipynb	dashboard.ipynb	gridspecLayout.ipynb	interactive.ipynb	ipympl.ipynb	mimerenderers.ipynb	bokeh.ipynb	multiple_widgets.ipynb	query-strings.ipynb	reveal.ipynb
Render
chromium
actual	84 <- [91 - 101 - 130] -> 204	70 <- [74 - 79 - 91] -> 129	71 <- [73 - 82 - 92] -> 119	65 <- [68 - 74 - 89] -> 113	2647 <- [2751 - 2823 - 2910] -> 4038	2255 <- [2324 - 2332 - 2459] -> 2653	2419 <- [2451 - 2455 - 2599] -> 2685	2498 <- [2516 - 2518 - 2564] -> 2629	1945 <- [1962 - 1995 - 2123] -> 2353	3052 <- [3131 - 3156 - 3206] -> 3651	7424 <- [7639 - 7645 - 7654] -> 7697	3544 <- [3580 - 3601 - 3617] -> 3857	3856 <- [3889 - 3914 - 3990] -> 4209	1580 <- [1593 - 1600 - 1621] -> 1676	2908 <- [2908 - 2945 - 2983] -> 3250
expected	3379 <- [3442 - 3517 - 3701] -> 3876	2976 <- [3227 - 3321 - 3421] -> 3604	3608 <- [3623 - 3709 - 3793] -> 3825	4453 <- [4453 - 4523 - 4661] -> 4748	2559 <- [2655 - 2656 - 2660] -> 2674	3982 <- [4079 - 4213 - 4356] -> 4743	12183 <- [18509 - 19553 - 20811] -> 21515	15319 <- [15660 - 15796 - 15912] -> 16056	1517 <- [1920 - 1997 - 2103] -> 2113

❗ Test metadata have changed

--- /dev/fd/63	2023-06-23 16:22:19.186233515 +0000
+++ /dev/fd/62	2023-06-23 16:22:19.186233515 +0000
@@ -4,51 +4,49 @@
     "BENCHMARK_REFERENCE": "actual"
   },
   "browsers": {
-    "chromium": "112.0.5615.29"
+    "chromium": "94.0.4595.0"
   },
   "systemInformation": {
     "cpu": {
-      "brand": "Xeon® Platinum 8370C",
+      "brand": "Xeon® E5-2673 v3",
       "cache": {
-        "l1d": 98304,
+        "l1d": 65536,
         "l1i": 65536,
-        "l2": 2097152,
-        "l3": 50331648
+        "l2": 524288,
+        "l3": 31457280
       },
       "cores": 2,
-      "efficiencyCores": 0,
       "family": "6",
-      "flags": "fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology cpuid pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single pti fsgsbase bmi1 hle avx2 smep bmi2 erms invpcid rtm avx512f avx512dq rdseed adx smap clflushopt avx512cd avx512bw avx512vl xsaveopt xsavec xsaves md_clear",
+      "flags": "fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology cpuid pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm abm invpcid_single pti fsgsbase bmi1 avx2 smep bmi2 erms invpcid xsaveopt md_clear",
       "governor": "",
-      "manufacturer": "Intel",
-      "model": "106",
-      "performanceCores": 2,
+      "manufacturer": "Intel®",
+      "model": "63",
       "physicalCores": 2,
       "processors": 1,
       "revision": "",
       "socket": "",
-      "speed": 2.8,
+      "speed": 2.4,
       "speedMax": null,
       "speedMin": null,
-      "stepping": "6",
-      "vendor": "Intel",
+      "stepping": "2",
+      "vendor": "GenuineIntel",
       "virtualization": false,
       "voltage": ""
     },
     "mem": {
-      "total": 7268679680
+      "total": 7291699200
     },
     "osInfo": {
       "arch": "x64",
       "build": "",
-      "codename": "Jammy Jellyfish",
+      "codename": "Focal Fossa",
       "codepage": "UTF-8",
       "distro": "Ubuntu",
-      "kernel": "5.15.0-1040-azure",
+      "kernel": "5.8.0-1040-azure",
       "logofile": "ubuntu",
       "platform": "linux",
-      "release": "22.04.2 LTS",
-      "serial": "b53da094229547778a51a873666147e4",
+      "release": "20.04.3 LTS",
+      "serial": "cfc067bfcb844f35865e279a1b0e66c5",
       "servicepack": "",
       "uefi": false
     }

[trungleduc]

Thanks @davidbrochart !