Fix: Updated allowed method lists for legacy-global-source and legacy-mount-source

For legacy-global-source this adds POST to the list.
For legacy-mount-source this adds POST and DELETE to the list.
The lists are now sync.

Closes: #2366
Found while working on & See also: icecast-libshout#2303
1 job from master in 17 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Build
failed #557
docker alpine
build

00:00:17

 
Name Stage Failure
failed
build Build There is an unknown failure, please try again
  openssl-dev-1.0.2q-r0:
conflicts:
libressl-dev-2.7.4-r0[pc:libcrypto=1.0.2q]
libressl-dev-2.7.4-r0[pc:libssl=1.0.2q]
libressl-dev-2.7.4-r0[pc:openssl=1.0.2q]
satisfies: world[openssl-dev]
libssh2-dev-1.8.0-r3[pc:libcrypto]
libssh2-dev-1.8.0-r3[pc:libssl]
ERROR: Job failed: exit code 4