Utilize the mounted disk space for some CI operations

The CI checkout, build step, & node & node modules take more than >20-30GBs. We have 71GB mounted disk that we can use.

Filesystem      Size  Used Avail Use% Mounted on
  /dev/root        73G   44G   29G  [6](https://github.com/apache/airflow-site/actions/runs/10413031045/job/28839980451#step:8:7)1% /
  tmpfs           7.9G  1[7](https://github.com/apache/airflow-site/actions/runs/10413031045/job/28839980451#step:8:8)2K  7.9G   1% /dev/shm
  tmpfs           3.2G  1.1M  3.2G   1% /run
  tmpfs           5.0M     0  5.0M   0% /run/lock
  /dev/sda15      105M  6.1M   [9](https://github.com/apache/airflow-site/actions/runs/10413031045/job/28839980451#step:8:10)9M   6% /boot/efi
  /dev/sdb1        74G   27G   43G  39% /mnt
  tmpfs           1.6G   12K  1.6G   1% /run/user/[10](https://github.com/apache/airflow-site/actions/runs/10413031045/job/28839980451#step:8:11)01

after docs were built:

df -h
  Filesystem      Size  Used Avail Use% Mounted on
  /dev/root        73G   46G   28G  63% /
  tmpfs           7.9G  172K  7.9G   1% /dev/shm
  tmpfs           3.2G  1.1M  3.2G   1% /run
  tmpfs           5.0M     0  5.0M   0% /run/lock
  /dev/sdb15      105M  6.1M   99M   6% /boot/efi
  /dev/sda1        74G   51G   20G  72% /mnt
  tmpfs           1.6G   12K  1.6G   1% /run/user/1001

Once node modules are removed:

Filesystem      Size  Used Avail Use% Mounted on
  /dev/root        73G   45G   28G  62% /
  tmpfs           7.9G  172K  7.9G   1% /dev/shm
  tmpfs           3.2G  1.1M  3.2G   1% /run
  tmpfs           5.0M     0  5.0M   0% /run/lock
  /dev/sda[15](https://github.com/apache/airflow-site/actions/runs/10413031045/job/28839980451#step:22:16)      105M  6.1M   99M   6% /boot/efi
  /dev/sdb1        74G  4.8G   65G   7% /mnt
  tmpfs           1.6G   12K  1.6G   1% /run/user/1001

https://github.com/apache/airflow-site/actions/runs/10413031045/job/28839980451

apache / airflow-site

Utilize the mounted disk space for some CI operations #1055